Consider the following statements regarding Structural control on Himalayan valley morphology:
1. The Main Boundary Thrust (MBT) separates the Lesser Himalayas from the Sub-Himalayas and exerts primary control over the longitudinal orientation of the Dun valleys.
2. The transverse drainage patterns of the Indus and Brahmaputra rivers, which predate the uplift of the Greater Himalayas, indicate that the Himalayan valley morphology is influenced by antecedent river systems.
3. The Indus-Tsangpo Suture Zone (ITSZ) represents the collision boundary between the Indian and Tibetan plates, and it acts as the primary catchment area for the formation of the longitudinal valleys in the Lesser Himalayas.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as the MBT acts as a tectonic boundary facilitating the formation of longitudinal structural valleys known as Duns. Statement 2 is correct because the Indus and Brahmaputra are antecedent rivers that maintained their courses through deep gorges despite the ongoing tectonic uplift of the Himalayas. Statement 3 is incorrect because the ITSZ marks the suture between the Indian and Eurasian plates, whereas the longitudinal valleys of the Lesser Himalayas are primarily controlled by the MBT and Main Central Thrust (MCT), not the ITSZ.
Consider the following statements regarding Tectonic uplift rates and fluvial incision cycles:
1. The Main Boundary Thrust (MBT) exhibits varying slip rates, with geodetic measurements indicating uplift rates of approximately 2 to 5 millimeters per year in the central Himalayan sector.
2. The Indus River demonstrates a high incision rate of 10 millimeters per year near the Nanga Parbat massif, a phenomenon primarily driven by the rapid subduction of the Indian Plate beneath the Eurasian Plate at the Tethys suture zone.
3. The Great Himalayan Range experienced a significant phase of crustal thickening during the Eocene epoch, which resulted in the formation of the Main Central Thrust and the subsequent cessation of all fluvial erosion in the Lesser Himalayas.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is correct as geodetic data confirms that the Main Boundary Thrust (MBT) experiences active crustal shortening and uplift rates in the range of 2-5 mm/year in the central Himalayas. Statement 2 is incorrect because while the Indus River exhibits rapid incision near Nanga Parbat, it is primarily driven by localized tectonic exhumation and climate-induced erosion rather than subduction at the Tethys suture zone, which is a legacy feature. Statement 3 is incorrect because the formation of the Main Central Thrust (MCT) did not cause a cessation of fluvial erosion; in fact, the uplift associated with crustal thickening has historically accelerated fluvial incision and landscape denudation in the Lesser Himalayas.
Consider the following statements regarding Trans-Himalayan Tethyan sedimentary sequences:
1. The Krol Belt, while often associated with the Lesser Himalaya, shares lithological affinities with the Tethyan sequences through the presence of carbonate-dominated successions deposited during the late Paleozoic.
2. The Indus Suture Zone marks the tectonic boundary where the Tethyan sedimentary sequences were deformed and thrusted southward during the final closure of the Neo-Tethys Ocean.
3. The Spiti Valley in Himachal Pradesh is widely recognized for its fossiliferous marine strata, particularly the Lilang Group, which documents the Triassic-Jurassic boundary transition.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct as the Krol Belt contains late Paleozoic carbonate successions that reflect the shallow marine conditions characteristic of the Tethyan realm. Statement 2 is correct because the Indus Suture Zone (ISZ) represents the collisional interface where the Neo-Tethys Ocean closed, leading to the southward thrusting of Tethyan sediments onto the Indian plate. Statement 3 is correct because the Spiti Valley's Lilang Group is a world-renowned geological reference section that provides a continuous, fossil-rich record of marine sedimentation across the Triassic-Jurassic boundary.
Consider the following statements regarding Hydro-geological characteristics of the Siwalik molasse:
1. The Main Boundary Thrust (MBT) acts as a structural interface that influences the groundwater flow patterns within the Siwalik foothills by compartmentalizing the sedimentary basins.
2. The Siwalik Group was deposited during the Eocene epoch as a result of marine transgression, and these early marine sediments provide the primary saline groundwater reservoirs found in the foothills today.
3. The Siwalik molasse, primarily composed of Neogene sedimentary deposits, exhibits high porosity in the sandstone units which facilitates the infiltration of meteoric water into deeper aquifers.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 3 is correct. Statement 2 is incorrect.
Statement 1 is correct as the Main Boundary Thrust (MBT) acts as a significant tectonic barrier that disrupts continuous aquifers, compartmentalizing groundwater flow within the Siwalik foothills. Statement 3 is correct because the Siwalik molasse, formed during the Neogene period, consists of coarse-grained fluvial sandstone units with high primary porosity, which are crucial for the recharge of deep-seated aquifers. Statement 2 is incorrect because the Siwalik Group is a product of continental (fluvial) sedimentation resulting from the erosion of the rising Himalayas during the Miocene to Pleistocene epochs, not an Eocene marine transgression.
Consider the following statements regarding Metamorphic facies of the Higher Himalayan Crystalline:
1. Kyanite-sillimanite transition zones within the Higher Himalayan Crystalline are often identified by the presence of migmatites, indicating partial melting at temperatures exceeding 650 degrees Celsius.
2. The metamorphic peak of the Higher Himalayan Crystalline in the Zanskar region is dated to approximately 20 to 22 million years ago, coinciding with the early Miocene period.
3. High-pressure granulite facies rocks, defined by the presence of omphacite and garnet, are exposed along the entire southern front of the Main Central Thrust, marking the initial subduction phase of the Indian plate during the Eocene epoch.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct because the onset of partial melting (anatexis) in pelitic rocks typically occurs above 650°C, leading to the formation of migmatites in the kyanite-sillimanite transition zone. Statement 2 is correct as geochronological data from the Zanskar region confirms the peak metamorphic event occurred during the early Miocene (20-22 Ma) due to crustal thickening. Statement 3 is incorrect because high-pressure granulites and eclogites (containing omphacite) are not exposed along the entire southern front of the Main Central Thrust; instead, they are restricted to specific tectonic windows like the Tso Morari complex, which represents a distinct subduction-related event rather than the general Himalayan crystalline sequence.
Consider the following statements regarding Isostatic equilibrium and Himalayan orogeny:
1. The Main Central Thrust (MCT) represents a major crustal-scale fault zone that separates the Higher Himalayas from the Lesser Himalayas, reflecting the tectonic shortening processes active since the Miocene.
2. According to the Pratt model of isostasy, the varying elevations of the Himalayan peaks are compensated by lateral variations in rock density, where higher mountains possess a proportionally lower crustal density.
3. Geodetic measurements indicate that the convergence rate between the Indian and Eurasian plates remains active at approximately 40 to 50 millimeters per year, contributing to the ongoing crustal thickening of the Tibetan Plateau.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct as the MCT is a major tectonic boundary formed during the Miocene epoch that facilitates the southward thrusting of the Higher Himalayas over the Lesser Himalayas. Statement 2 is correct because the Pratt model posits that crustal blocks of varying elevations maintain isostatic equilibrium through density variations, where higher topography is compensated by underlying lower-density roots. Statement 3 is correct as modern GPS and geodetic data confirm a continuous convergence rate of 40-50 mm/year between the Indian and Eurasian plates, which drives the ongoing uplift and crustal thickening of the Himalayan-Tibetan orogenic system.
Consider the following statements regarding Tectonic uplift rates and fluvial incision cycles:
1. Cosmogenic nuclide dating of river terraces along the Alaknanda River suggests that incision rates accelerated during the late Pleistocene, coinciding with the retreat of the Gangotri Glacier and the stabilization of the Main Boundary Thrust.
2. Isostatic rebound following the melting of extensive ice sheets in the Zanskar Range has contributed to a localized increase in fluvial incision, a process that is currently balanced by the ongoing deposition of loess in the Kashmir Basin.
3. The Kosi River fan exhibits a complex history of avulsion and incision, where the rate of sediment transport is determined by the high-frequency tectonic uplift of the Tibetan Plateau and the resulting base-level lowering of the Ganges Plain.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because cosmogenic nuclide dating typically links incision to climatic shifts and monsoon intensification rather than the stabilization of the Main Boundary Thrust, which remains tectonically active. Statement 2 is false as the Kashmir Basin's loess deposits are primarily paleoclimatic records of arid-humid cycles, not a mechanism balancing post-glacial isostatic rebound in the Zanskar Range. Statement 3 is incorrect because the Kosi River's avulsion is driven by high sediment flux from the rapid erosion of the Himalayas and the tectonic subsidence of the Indo-Gangetic foreland basin, not by the uplift of the Tibetan Plateau.
Consider the following statements regarding Metamorphic facies of the Higher Himalayan Crystalline:
1. The Main Central Thrust (MCT) serves as the southern tectonic boundary of the Higher Himalayan Crystalline, separating it from the Lesser Himalayan sequence to the south.
2. The Higher Himalayan Crystalline sequence is primarily characterized by Barrovian-type metamorphism, exhibiting a progressive increase in metamorphic grade from greenschist to amphibolite facies.
3. The Higher Himalayan Crystalline exhibits a distinct Buchan-type metamorphic facies series, characterized by the widespread occurrence of andalusite and cordierite assemblages consistent with the rapid exhumation rates observed in the 15 million-year-old Karakoram sequences.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as the Main Central Thrust (MCT) acts as the fundamental tectonic boundary separating the high-grade Higher Himalayan Crystalline (HHC) from the underlying Lesser Himalayan sequence. Statement 2 is correct because the HHC is defined by classic Barrovian metamorphism, showing a systematic progression from greenschist to upper-amphibolite and granulite facies due to crustal thickening. Statement 3 is incorrect because the HHC is characterized by Barrovian (high-pressure/medium-temperature) facies rather than Buchan-type (low-pressure/high-temperature) facies, and the presence of andalusite/cordierite is not a defining feature of the HHC sequence.
Consider the following statements regarding Orogenic belt seismicity and crustal shortening:
1. Crustal shortening in the Himalayas is accommodated by the detachment of the Indian lithospheric mantle, which is currently undergoing subduction at a steep angle of 60 degrees beneath the Indus-Tsangpo Suture Zone.
2. The Indo-Gangetic Plain acts as a foreland basin formed by the flexural loading of the Indian plate, where the sediment thickness reaches 10 kilometers due to the rapid subsidence caused by the Main Boundary Thrust activity.
3. Seismic tomography studies of the Himalayan arc reveal that the Indian plate crust is currently undergoing delamination at a depth of 150 kilometers, which triggers the high-frequency volcanic activity observed in the Zanskar range.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the Indian plate subducts at a very shallow angle (typically 5-15 degrees) rather than 60 degrees. Statement 2 is incorrect because while the Indo-Gangetic Plain is a foreland basin, the sediment thickness is generally 2-6 km, and its formation is primarily linked to the flexural downwarping of the Indian plate rather than being solely attributed to the Main Boundary Thrust. Statement 3 is incorrect because the Himalayas are a continent-continent collision zone characterized by a lack of active volcanism, and there is no evidence of high-frequency volcanic activity in the Zanskar range.
Consider the following statements regarding Orogenic belt seismicity and crustal shortening:
1. The Main Central Thrust (MCT) represents the northernmost boundary of the Himalayan orogenic belt and is responsible for the subduction of the Tethyan oceanic crust beneath the Tibetan Plateau.
2. The 2015 Gorkha earthquake, which registered a magnitude of 7.8, occurred due to the slip along the Main Himalayan Thrust (MHT) beneath the Kathmandu basin.
3. The Main Boundary Thrust (MBT) separates the Lesser Himalayas from the Sub-Himalayas and exhibits significant crustal shortening of approximately 15 to 20 millimeters per year.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 2 is correct. Statement 3 is correct. Statement 1 is incorrect.
Statement 1 is incorrect because the MCT is not the northernmost boundary; the Indus-Tsangpo Suture Zone (ITSZ) marks the collision boundary, and the MCT represents a mid-crustal shear zone within the Himalayas, not the subduction of Tethyan oceanic crust. Statement 2 is correct as the 2015 Gorkha earthquake resulted from the release of accumulated strain along the Main Himalayan Thrust (MHT), the primary decollement fault where the Indian plate underthrusts the Eurasian plate. Statement 3 is correct because the MBT marks the tectonic contact between the Lesser and Sub-Himalayas, and geodetic measurements confirm that the ongoing convergence of the Indian plate continues to drive crustal shortening at rates of approximately 15-20 mm/year across these fault systems.
Consider the following statements regarding Paleoclimatic signatures in Himalayan loess deposits:
1. Himalayan loess deposits in the Kashmir Valley, particularly in the Karewa formations, provide a continuous record of paleoclimatic fluctuations spanning the last 3.5 million years.
2. The magnetic susceptibility (MS) signal in the loess-paleosol sequences of the Kashmir basin serves as a proxy for summer monsoon intensity, with higher values indicating increased pedogenesis during warmer, wetter periods.
3. Geochemical analysis of the loess deposits reveals that the source of the silt-sized particles is primarily glacial flour transported by the prevailing westerlies from the surrounding high-altitude mountain ranges.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct as the Karewa formations contain thick, undisturbed loess-paleosol sequences that act as a terrestrial archive spanning approximately 3.5 million years. Statement 2 is correct because magnetic susceptibility in these deposits correlates with the degree of soil formation (pedogenesis), which is driven by higher rainfall and temperature associated with intensified summer monsoons. Statement 3 is correct as the mineralogical and geochemical composition of the silt confirms it is 'glacial flour' derived from the mechanical weathering of rocks by glaciers, subsequently transported and deposited by wind systems like the westerlies.
Consider the following statements regarding Geodynamic implications of the Himalayan-Tibetan Plateau system:
1. The Indus-Tsangpo Suture Zone marks the geological boundary where the Tethys Ocean crust was subducted during the initial phase of continental collision.
2. The Karakoram Fault system acts as a dextral strike-slip boundary that facilitated the eastward extrusion of the Tibetan block during the Eocene epoch of the Paleogene period.
3. Isostatic compensation in the Himalayas is supported by a crustal root that extends to depths of 70 to 80 kilometers beneath the mountain range.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 3 is correct. Statement 2 is incorrect.
Statement 1 is correct as the Indus-Tsangpo Suture Zone represents the collisional boundary between the Indian and Eurasian plates where the Tethys Ocean crust was consumed. Statement 3 is correct because the Airy-Heiskanen model of isostasy confirms that the Himalayas maintain equilibrium through a deep crustal root reaching 70-80 km, compensating for the high surface elevation. Statement 2 is incorrect because while the Karakoram Fault is a dextral strike-slip system, the eastward extrusion of the Tibetan block occurred primarily during the Miocene epoch (starting ~20 million years ago), not the Eocene epoch.
Consider the following statements regarding Cryospheric dynamics and permafrost degradation:
1. The 2022 study published in the journal 'Nature' identifies that the elevation-dependent warming in the Himalayas causes high-altitude regions to experience temperature increases at a rate 1.5 times faster than the global average.
2. Permafrost degradation in the Zanskar Range has been linked to the 2013 Kedarnath disaster, where the rapid melting of ice-rich debris slopes contributed to the surge of glacial lake outburst floods.
3. The 2019 assessment by the International Centre for Integrated Mountain Development (ICIMOD) indicates that even under a 1.5-degree Celsius global warming scenario, at least one-third of the Hindu Kush Himalayan glaciers will likely melt by 2100.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct as high-altitude warming in the Himalayas is amplified by elevation-dependent warming, consistently reported at 1.5 times the global average in recent climate studies. Statement 2 is correct because the 2013 Kedarnath disaster was exacerbated by the destabilization of ice-rich permafrost and debris slopes, which contributed to the catastrophic surge of water and sediment. Statement 3 is correct as the 2019 ICIMOD assessment highlighted that even with aggressive climate mitigation, one-third of the Hindu Kush Himalayan glaciers face inevitable melting by 2100 due to the region's high climate sensitivity.
Consider the following statements regarding Drainage evolution of antecedent river systems:
1. The Arun River, a major tributary of the Kosi, maintains a deep gorge across the Greater Himalayas, serving as a classic example of antecedent drainage where the rate of river incision kept pace with tectonic uplift.
2. The Kosi River, known for its high sediment load, originates from the Tibetan plateau and follows a purely consequent drainage pattern determined by the post-Miocene tilting of the Indo-Gangetic plain.
3. The 1954 Agreement on Trade and Intercourse between India and Tibet established the current drainage divide between the Ganges and the Brahmaputra basins, effectively stabilizing the river courses in the Sikkim region.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is correct because the Arun River is a classic antecedent stream that maintained its course through the rising Himalayas via vertical erosion. Statement 2 is incorrect because the Kosi system is primarily antecedent, not consequent, as it predates the uplift of the Himalayas. Statement 3 is incorrect because the 1954 Agreement focused on trade and diplomatic relations, having no role in defining geological drainage divides or stabilizing river courses.
Consider the following statements regarding Cryospheric dynamics and permafrost degradation:
1. The 1994 United Nations Framework Convention on Climate Change (UNFCCC) includes provisions for the Himalayan Permafrost Mapping Project, which utilizes the 2015 Paris Agreement baseline to measure sub-surface soil temperatures.
2. The 2008 National Action Plan on Climate Change (NAPCC) launched the National Mission for Sustaining the Himalayan Ecosystem, which officially categorized the Gangotri glacier as a stable ice mass based on satellite telemetry from 2010.
3. The 1972 Stockholm Conference on the Human Environment established the Global Cryosphere Watch, which currently monitors permafrost thermal regimes across the Karakoram and the Pamir Knot.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
All three statements are incorrect because they contain fabricated institutional mandates and historical inaccuracies. The UNFCCC does not include a specific Himalayan Permafrost Mapping Project, the National Mission for Sustaining the Himalayan Ecosystem (NMSHE) under the NAPCC does not categorize glaciers as 'stable' (as most are retreating), and the Global Cryosphere Watch was established by the World Meteorological Organization in 2011, not the 1972 Stockholm Conference.
Consider the following statements regarding Cryospheric dynamics and permafrost degradation:
1. The 2014 IPCC Fifth Assessment Report highlights that the Hindu Kush Himalayas contain the largest volume of ice outside the polar regions, and notes that the Indus basin relies on seasonal snowmelt for 80 percent of its annual discharge.
2. The 2017 study by the Geological Survey of India observed that the Siachen Glacier has shifted its equilibrium line altitude by 50 meters, a process attributed to the 1991 Montreal Protocol mitigation targets.
3. The 2005 Disaster Management Act provides for the establishment of the National Institute of Disaster Management, which documented that the 2021 Chamoli flood was triggered by a volcanic eruption beneath the Nanda Devi massif.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because while the Hindu Kush Himalayas are known as the 'Third Pole,' the IPCC reports attribute the Indus basin's high dependency on snowmelt to approximately 40-50%, not 80%. Statement 2 is incorrect as the Montreal Protocol focuses on ozone-depleting substances, not glacier equilibrium shifts, and the Siachen Glacier's retreat is primarily linked to regional warming trends rather than ozone mitigation. Statement 3 is incorrect because the 2021 Chamoli disaster was caused by a massive rock and ice avalanche triggered by a landslide, not a volcanic eruption, as the Nanda Devi massif is not volcanic.
Consider the following statements regarding Stratigraphic classification of the Lesser Himalayas:
1. The Lesser Himalayas, also known as the Himachal, are primarily composed of highly compressed and altered rocks dating back to the Precambrian and Paleozoic eras.
2. The Dagshai Formation consists of red sandstones and clays deposited during the Eocene epoch, and it serves as the primary stratigraphic marker for the base of the Lesser Himalayan metamorphic core.
3. The Chandpur Formation is characterized by phyllites and quartzites, and it represents the youngest stratigraphic unit within the Lesser Himalayan sequence that was deposited during the late Miocene uplift.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is correct because the Lesser Himalayas are indeed composed of highly compressed, altered, and metamorphosed Precambrian and Paleozoic rocks. Statement 2 is incorrect because the Dagshai Formation belongs to the Subathu Group of the Siwalik/Outer Himalayan sequence, not the Lesser Himalayan metamorphic core. Statement 3 is incorrect because the Chandpur Formation consists of Proterozoic phyllites and quartzites, making it one of the older stratigraphic units rather than a late Miocene deposit.
Consider the following statements regarding Tectonic evolution of the Indus-Tsangpo Suture Zone:
1. The Shyok Suture Zone is situated to the south of the Indus-Tsangpo Suture Zone and represents the primary location of the initial subduction of the Indian continental margin beneath the Karakoram block.
2. The Zanskar Shear Zone serves as the northernmost limit of the Indus-Tsangpo Suture Zone, acting as a structural boundary that separates the Tethyan Himalayan sequence from the Ladakh Batholith.
3. The Indus-Tsangpo Suture Zone marks the tectonic boundary where the Indian Plate collided with the Eurasian Plate during the Eocene epoch, approximately 50 million years ago.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct as the Indus-Tsangpo Suture Zone (ITSZ) represents the major collisional boundary formed by the closure of the Neo-Tethys Ocean and the collision of the Indian and Eurasian plates during the Eocene (~50 Ma). Statement 1 is incorrect because the Shyok Suture Zone is located north of the ITSZ, representing the collision between the Ladakh Batholith and the Karakoram block, not the Indian margin. Statement 2 is incorrect because the Zanskar Shear Zone is a mid-crustal extensional feature located within the Tethyan Himalayan sequence, whereas the northern boundary of the ITSZ is defined by the Indus Thrust separating the suture zone from the Ladakh Batholith.
Consider the following statements regarding Hydro-geological characteristics of the Siwalik molasse:
1. The Upper Siwalik conglomerates, known as the Boulder Conglomerate stage, contain high concentrations of metamorphic limestone that increase the alkalinity of the groundwater throughout the entire Himalayan foreland basin.
2. Geophysical surveys of the Siwalik molasse identify the existence of widespread, continuous karst aquifers that extend from the Indus River in the west to the Brahmaputra in the east.
3. The Lower Siwalik sequence is defined by the Chinji Formation, which consists of massive conglomerate beds that facilitate rapid groundwater recharge into the underlying Precambrian basement rocks.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the Boulder Conglomerate stage is primarily composed of lithic fragments derived from the rising Himalayas, and groundwater alkalinity in the foreland basin is governed by regional mineralogy rather than a uniform metamorphic limestone influence. Statement 2 is incorrect as the Siwalik molasse consists of heterogeneous, discontinuous fluvial deposits that do not support widespread, continuous karst aquifers, which are typically restricted to specific carbonate terrains. Statement 3 is incorrect because the Chinji Formation of the Lower Siwalik is characterized by fine-grained sandstones, siltstones, and clays-not massive conglomerates-and it acts as an aquitard rather than a conduit for rapid recharge into the Precambrian basement.
Consider the following statements regarding Tectonic evolution of the Indus-Tsangpo Suture Zone:
1. Ophiolitic sequences, including peridotites and pillow lavas found within the Indus-Tsangpo Suture Zone, represent remnants of the Neo-Tethyan oceanic crust trapped during the continental collision.
2. Sedimentary deposits known as the Indus Group are characterized by marine limestone sequences that record the shallow-water environment present in the suture zone during the post-collisional Pliocene epoch.
3. The Kohistan-Ladakh Arc represents an intra-oceanic volcanic chain that accreted to the Eurasian margin during the Jurassic, effectively closing the Indus-Tsangpo Suture Zone before the Indian Plate arrived.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is correct because ophiolites in the Indus-Tsangpo Suture Zone are indeed obducted fragments of the Neo-Tethyan oceanic lithosphere marking the boundary between the Indian and Eurasian plates. Statement 2 is incorrect because the Indus Group consists primarily of continental and fluvio-deltaic deposits formed during the Eocene, not marine limestone from the Pliocene. Statement 3 is incorrect because the Kohistan-Ladakh Arc accreted to the Eurasian margin during the Cretaceous (approx. 100-60 Ma), long after the Jurassic, and the suture zone closed only after the subsequent collision of the Indian Plate.
Consider the following statements regarding Geochemical weathering and carbon sequestration rates:
1. Research published in the journal 'Nature' in 2017 suggests that the chemical weathering of Himalayan rocks acts as a significant long-term sink for atmospheric carbon dioxide over geological timescales.
2. The weathering of carbonate minerals in the Himalayas, while rapid, often results in a net neutral carbon balance because the release of CO2 during carbonate precipitation in oceans offsets the initial sequestration.
3. The Himalayan Orogeny, which began approximately 50 million years ago, is characterized by the dominance of basaltic rock weathering, which accounts for the primary sequestration of atmospheric carbon dioxide in the Indus-Ganges plain.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as silicate weathering in the Himalayas consumes atmospheric CO2, sequestering it as bicarbonate ions transported to oceans. Statement 2 is correct because carbonate weathering is a closed loop where the CO2 consumed on land is released back into the atmosphere when marine organisms precipitate calcium carbonate. Statement 3 is incorrect because the Himalayan Orogeny is primarily characterized by the weathering of silicate and carbonate rocks (metamorphic and sedimentary), not basaltic rocks, which are more typical of Large Igneous Provinces like the Deccan Traps.
Consider the following statements regarding Geodynamic implications of the Himalayan-Tibetan Plateau system:
1. The High Himalayan Crystalline sequence consists of Proterozoic metamorphic rocks that were exhumed during the Miocene period due to the Main Central Thrust activity.
2. The Main Frontal Thrust represents the southernmost active fault of the Himalayan system, which recorded significant displacement during the 1934 Bihar-Nepal earthquake event.
3. The South Tibetan Detachment System is a north-dipping normal fault zone that accommodated the gravitational collapse of the thickened Tibetan crust during the Early Miocene.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 3 is correct. Statement 2 is incorrect.
Statement 1 is correct as the High Himalayan Crystalline sequence comprises Proterozoic rocks exhumed via the Main Central Thrust (MCT) during the Miocene. Statement 3 is correct because the South Tibetan Detachment System (STDS) is a north-dipping normal fault that facilitated the gravitational collapse of the over-thickened Tibetan crust during the Early Miocene. Statement 2 is incorrect because, while the Main Frontal Thrust (MFT) is indeed the southernmost active fault, the 1934 Bihar-Nepal earthquake was primarily associated with the Main Boundary Thrust (MBT) or a blind thrust segment, rather than significant surface displacement along the MFT.
Consider the following statements regarding Structural anatomy of the Main Central Thrust:
1. Geological mapping indicates that the MCT originated approximately 20 to 23 million years ago during the early Miocene epoch as a result of continental collision.
2. The Main Central Thrust (MCT) represents a crustal-scale ductile shear zone that separates the Greater Himalayan Sequence from the underlying Lesser Himalayan Sequence.
3. The Main Central Thrust is defined by the juxtaposition of the Tethyan Sedimentary Series against the Lesser Himalayan Sequence, a process completed during the late Eocene period.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as the MCT initiated during the early Miocene (approx. 20-23 Ma) due to the ongoing India-Asia collision. Statement 2 is correct because the MCT is a major crustal-scale ductile shear zone that thrusts the high-grade metamorphic rocks of the Greater Himalayan Sequence (GHS) over the lower-grade Lesser Himalayan Sequence (LHS). Statement 3 is incorrect because the Tethyan Sedimentary Series is separated from the Greater Himalayan Sequence by the South Tibetan Detachment System (STDS), not the MCT, and the MCT's activity is linked to the Miocene rather than the late Eocene.
Consider the following statements regarding Lithospheric flexure and foreland basin development:
1. The Main Frontal Thrust marks the southern boundary of the Himalayan orogenic belt, and its activity is characterized by the rapid uplift of the Lesser Himalayas since the late Cretaceous period.
2. The Indo-Gangetic Plain functions as a peripheral foreland basin formed due to the lithospheric flexure of the Indian Plate as it subducts beneath the Eurasian Plate.
3. The Siwalik Group represents the primary sediment infill of the foreland basin, with the depositional sequence initiating during the Eocene epoch approximately 50 million years ago.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 2 is correct. Statement 1 is incorrect. Statement 3 is incorrect.
Statement 2 is correct because the Indo-Gangetic Plain is a classic peripheral foreland basin created by the downward flexure of the Indian lithosphere under the load of the advancing Himalayan orogenic wedge. Statement 1 is incorrect because the Main Frontal Thrust (MFT) is a relatively young feature, with significant activity occurring primarily during the Pliocene-Pleistocene epochs, not the late Cretaceous. Statement 3 is incorrect because, while the Siwaliks represent the foreland basin fill, the depositional sequence began significantly later, around 15-20 million years ago during the Miocene, rather than 50 million years ago in the Eocene.
Consider the following statements regarding Hydro-geological characteristics of the Siwalik molasse:
1. The presence of interbedded clay lenses within the Siwalik molasse sequences creates localized confined aquifer conditions, which are frequently tapped by tube wells in the Terai region.
2. The Middle Siwalik subgroup is characterized by thick-bedded, grey, micaceous sandstones that demonstrate significant primary permeability compared to the finer-grained Lower Siwalik siltstones.
3. Hydro-geological investigations indicate that the Siwalik range serves as a critical recharge zone for the Indo-Gangetic plains, with the coarse alluvial fans at the mountain front acting as primary infiltration sites.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct because the heterogeneous lithology of the Siwalik molasse, featuring clay lenses, creates discontinuous confined aquifers essential for groundwater storage in the Terai. Statement 2 is correct as the Middle Siwalik sandstones possess higher porosity and primary permeability due to their coarser, micaceous composition compared to the low-permeability siltstones of the Lower Siwaliks. Statement 3 is correct because the high-energy depositional environment at the Himalayan mountain front creates massive, permeable alluvial fans that facilitate rapid infiltration, serving as the primary recharge mechanism for the underlying Indo-Gangetic aquifer system.
Consider the following statements regarding Lithospheric flexure and foreland basin development:
1. Isostatic compensation in the Himalayan region is achieved through the Airy model of crustal thickening, which accounts for the observed negative Bouguer gravity anomalies across the Tibetan Plateau.
2. The flexural rigidity of the Indian lithosphere, estimated at 10^23 to 10^25 Newton-meters, determines the wavelength and amplitude of the foreland basin subsidence.
3. The depth of the Gangetic foreland basin increases towards the Himalayan front, reaching a maximum sediment thickness of approximately 6 to 8 kilometers near the Main Boundary Thrust.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 2 is correct. Statement 3 is correct. Statement 1 is incorrect.
Statement 1 is incorrect because the Airy model, which assumes constant density and variable root depth, fails to explain the Himalayan-Tibetan region; instead, the Pratt model or a combination of crustal thickening and thermal buoyancy is required to account for the observed gravity anomalies. Statement 2 is correct as the Indian lithosphere acts as a flexed elastic plate, where the flexural rigidity (10^23-10^25 Nm) dictates the basin's geometry and subsidence patterns. Statement 3 is correct because the loading of the Himalayan orogenic wedge causes the Indian plate to flex downward, creating a peripheral foreland basin that deepens to 6-8 km near the Main Boundary Thrust (MBT) to accommodate sediment accumulation.
Consider the following statements regarding Lithospheric flexure and foreland basin development:
1. The Indus-Yarlung Suture Zone represents the site of initial continental collision, and the subsequent loading of the lithosphere led to the formation of the Tethyan Himalayan foredeep during the Miocene.
2. The flexural bulge of the Indian Plate, known as the Delhi-Hardwar ridge, acts as a sediment trap that limits the southward migration of the foreland basin depocenter.
3. Sedimentation rates in the Gangetic basin are primarily controlled by the monsoon-driven erosion of the Higher Himalayas, with the depocenter shifting northward since the Pliocene epoch.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the Tethyan Himalayan sequence represents pre-collisional shelf sediments, not a Miocene foredeep, which actually formed as the Siwalik foreland basin. Statement 2 is incorrect because the Delhi-Hardwar ridge is a basement high that acts as a structural barrier or 'hinge' rather than a sediment trap limiting southward migration; in fact, the depocenter migrates southward over time due to flexural loading. Statement 3 is incorrect because, while monsoon-driven erosion influences sedimentation, the foreland basin depocenter has been migrating southward toward the Indian craton since the Miocene, not northward.
Consider the following statements regarding Glacial geomorphology and moraine-dammed lakes:
1. The Imja Tsho glacial lake, located in the Khumbu region, experienced a rapid expansion during the 1990s and is currently classified by the Geological Survey of India as a permanent stable water body.
2. The Tsho Rolpa glacial lake in Nepal, situated at an altitude of approximately 4,580 meters, underwent a major mitigation project in 1998 involving the construction of an open channel to lower its water level by 3 meters.
3. Glacial Lake Outburst Floods (GLOFs) are primarily triggered by the accumulation of supraglacial debris, and the 1985 Dig Tsho flood in Nepal resulted in a discharge of approximately 6 million cubic meters of water into the Bhote Koshi river basin.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 2 is correct. Statement 1 is incorrect. Statement 3 is incorrect.
Statement 2 is correct as the Tsho Rolpa mitigation project in 1998 successfully lowered the lake level by 3 meters to reduce GLOF risks. Statement 1 is incorrect because Imja Tsho is not classified as a stable water body by the Geological Survey of India; rather, it remains a high-risk, rapidly expanding glacial lake. Statement 3 is incorrect because, while the 1985 Dig Tsho flood did occur, the discharge volume was approximately 6 million cubic meters, but GLOFs are primarily triggered by ice avalanches, moraine instability, or seismic activity, rather than the mere accumulation of supraglacial debris.
Consider the following statements regarding Geochemical weathering and carbon sequestration rates:
1. The formation of secondary clay minerals, such as kaolinite, during the hydrolysis of silicate minerals in the Himalayan soil profiles is a key mechanism for the permanent storage of carbon in geological formations.
2. Studies of the Indus River basin indicate that silicate weathering rates are disproportionately high in the Himalayan foothills compared to the Tibetan Plateau due to higher average temperatures and moisture availability.
3. Isotopic analysis of strontium (87Sr/86Sr ratios) in Himalayan river waters provides a proxy for measuring the intensity of silicate weathering and its contribution to global carbon cycling.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct because silicate hydrolysis consumes atmospheric CO2, converting it into bicarbonate ions that precipitate as secondary minerals like kaolinite, effectively sequestering carbon over geological timescales. Statement 2 is correct as the Himalayan foothills experience intense monsoon-driven precipitation and higher temperatures, which exponentially accelerate chemical weathering rates compared to the cold, arid conditions of the Tibetan Plateau. Statement 3 is correct because the 87Sr/86Sr ratio in riverine dissolved loads serves as a robust geochemical tracer, distinguishing between radiogenic strontium derived from silicate weathering and non-radiogenic strontium from carbonate dissolution, thereby quantifying the silicate-weathering-driven carbon sink.
Consider the following statements regarding Structural control on Himalayan valley morphology:
1. The transverse valleys of the Alaknanda and Bhagirathi rivers are governed by the presence of the Main Boundary Thrust, which forces these streams to flow parallel to the strike of the Greater Himalayan peaks.
2. The Siwalik Group consists of molasse deposits derived from the erosion of the rising Himalayas, and these sediments are structurally controlled by the Main Frontal Thrust, which was formed during the late Eocene period.
3. The formation of the Kathmandu valley is attributed to the damming of the Bagmati River by volcanic activity during the Pleistocene, which created a lacustrine environment that subsequently drained due to tectonic uplift.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the Alaknanda and Bhagirathi are antecedent rivers that cut across the strike of the Himalayas rather than flowing parallel to it. Statement 2 is false as the Main Frontal Thrust (MFT) is a much younger feature, having formed primarily during the late Miocene to Pliocene, not the Eocene. Statement 3 is incorrect because the Kathmandu Valley's lacustrine environment resulted from tectonic damming caused by the uplift of the Mahabharat Range, not volcanic activity.
Consider the following statements regarding Structural control on Himalayan valley morphology:
1. The Main Central Thrust (MCT) serves as the southern limit of the Siwalik range, facilitating the deposition of thick alluvial fans within the intermontane basins of the Kashmir valley.
2. The syntaxial bends at Nanga Parbat and Namcha Barwa are characterized by the convergence of the Eurasian and Indian plates, which causes the river valleys to follow a strictly north-south orientation across the entire range.
3. The Karewa formations in the Kashmir valley are primarily composed of glacial till deposited during the Pliocene epoch, which resulted from the tectonic subsidence of the Zanskar range.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the Main Boundary Thrust (MBT), not the MCT, marks the northern limit of the Siwaliks, while the Main Frontal Thrust (MFT) defines the southern boundary. Statement 2 is false as the syntaxial bends result in complex, often radial or antecedent drainage patterns rather than a strictly north-south orientation, influenced by the sharp tectonic curvature of the Himalayan orogen. Statement 3 is incorrect because Karewa formations are lacustrine (lake-deposited) sediments formed by the damming of the paleo-Kashmir valley due to tectonic uplift of the Pir Panjal range, rather than glacial till resulting from Zanskar subsidence.
Consider the following statements regarding Glacial geomorphology and moraine-dammed lakes:
1. The 2021 Chamoli disaster involved the rapid release of water from the Nanda Devi glacier, and subsequent satellite analysis confirmed that the event originated from a proglacial lake located at an altitude of 5,600 meters.
2. End moraines consist of unconsolidated rock fragments transported by ice, and the formation of the Roopkund Lake in Uttarakhand is linked to the blockage of a glacial cirque by these deposits during the Holocene thermal maximum.
3. Terminal moraines mark the maximum advance of a glacier, and the Wular Lake in the Kashmir Valley serves as a classic example of a basin formed by the damming of the Jhelum River by terminal moraine debris deposited during the Last Glacial Maximum.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the 2021 Chamoli disaster was triggered by a massive rock-ice avalanche from the Ronti Peak, not a proglacial lake outburst. Statement 2 is incorrect as Roopkund Lake is a high-altitude glacial lake formed by tectonic and glacial processes, but it is not linked to the Holocene thermal maximum. Statement 3 is incorrect because Wular Lake is a tectonic lake formed by the subsidence of the Kashmir Valley, not by the damming of the Jhelum River by terminal moraine debris.
Consider the following statements regarding Eolian processes in the high-altitude cold deserts:
1. Deflation hollows are common features in the high-altitude cold deserts, and the 2015 hydrological survey of the Changthang plateau identified these basins as being created by the seasonal melting of permafrost.
2. The process of abrasion in the cold desert of Ladakh involves the impact of wind-borne particles, and the 2001 mineralogical analysis indicated that these particles are predominantly composed of basaltic volcanic glass.
3. Wind-blown silt deposits in the Lahaul region are classified as periglacial loess, and the 1988 soil classification report linked their accumulation to the retreating monsoon winds of the Indian subcontinent.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because deflation hollows in high-altitude cold deserts are primarily formed by wind erosion (deflation) removing loose surface material, not by permafrost melting. Statement 2 is incorrect as the mineralogical composition of wind-borne particles in Ladakh is dominated by granitic and metamorphic rock fragments, not basaltic volcanic glass. Statement 3 is incorrect because while Lahaul features loess-like deposits, they are primarily aeolian accumulations linked to glacial outwash plains and katabatic winds, not the retreating monsoon.
Consider the following statements regarding Isostatic equilibrium and Himalayan orogeny:
1. The Airy hypothesis of isostasy suggests that the Himalayas maintain equilibrium by having a deep root of low-density crustal material extending into the denser mantle, analogous to an iceberg floating in water.
2. The collision between the Indian Plate and the Eurasian Plate, which initiated the Himalayan orogeny, is estimated to have commenced approximately 50 million years ago during the Eocene epoch.
3. The concept of isostatic rebound in the Himalayas is primarily driven by the melting of Pleistocene glaciers, a process that accounts for the majority of the current 5-millimeter annual uplift observed in the Zanskar Range.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as Airy's hypothesis posits that mountains have deep 'roots' of lighter crustal material extending into the denser mantle to maintain hydrostatic balance. Statement 2 is correct because the collision between the Indian and Eurasian plates began roughly 50 million years ago during the Eocene epoch, leading to the formation of the Himalayas. Statement 3 is incorrect because, while glacial isostatic adjustment occurs, the primary driver of the current Himalayan uplift is the ongoing tectonic convergence and crustal shortening between the Indian and Eurasian plates, not the melting of Pleistocene glaciers.
Consider the following statements regarding Structural anatomy of the Main Central Thrust:
1. The MCT zone is characterized by an inverted metamorphic gradient where high-grade metamorphic rocks, such as kyanite-sillimanite schists, are structurally positioned above lower-grade rocks.
2. The transition zone of the MCT typically displays a thickness ranging from 500 meters to 2 kilometers, depending on the intensity of the localized strain and shear deformation.
3. Seismic profiling across the Garhwal Himalaya identifies the MCT as a north-dipping fault system that facilitates the southward transport of the Himalayan crystalline nappes.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
The Main Central Thrust (MCT) is a major crustal-scale shear zone where high-grade metamorphic rocks (kyanite-sillimanite) were thrust over lower-grade rocks, creating a characteristic inverted metamorphic gradient. The MCT zone typically spans a thickness of 500 meters to 2 kilometers due to intense ductile shearing, and seismic studies confirm it is a north-dipping fault system responsible for the southward transport of the Greater Himalayan Crystalline (GHC) complex over the Lesser Himalayan sequence. Since all three statements accurately describe the geological and structural characteristics of the MCT, all are correct.
Consider the following statements regarding Tectonic evolution of the Indus-Tsangpo Suture Zone:
1. The Indus-Tsangpo Suture Zone exhibits a consistent east-west strike, and its structural evolution is defined by the development of the Main Boundary Thrust during the early Paleocene collision phase.
2. The Ladakh Batholith consists primarily of metamorphic gneiss and schist, which formed as a result of high-pressure metamorphism during the final suturing of the Indus-Tsangpo Suture Zone in the Miocene.
3. During the Late Cretaceous period, the closure of the Tethys Ocean initiated the formation of the Main Central Thrust, which currently defines the southern limit of the Indus-Tsangpo Suture Zone.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
All three statements are incorrect because the Indus-Tsangpo Suture Zone (ITSZ) marks the collision between the Indian and Eurasian plates, not the Main Boundary Thrust (MBT) or Main Central Thrust (MCT), which are younger crustal features located further south. The Ladakh Batholith is a magmatic arc composed of granitic rocks formed by subduction-related volcanism during the Cretaceous-Eocene, not metamorphic gneiss from Miocene suturing. Furthermore, the closure of the Tethys Ocean occurred during the Eocene, and the ITSZ defines the northern boundary of the Himalayan orogen, whereas the MCT and MBT developed significantly later during the ongoing continental collision.
Consider the following statements regarding Stratigraphic classification of the Lesser Himalayas:
1. The Shali Window in the Himachal Pradesh region exposes older carbonate rocks beneath the younger thrust sheets, providing evidence of the complex tectonic stacking of the Lesser Himalayas.
2. The Krol Group, a significant stratigraphic unit of the Lesser Himalayas, is characterized by a thick sequence of carbonate rocks including limestone, dolomite, and shale.
3. The Infra-Krol formation is distinguished by its dark, carbonaceous shales and siltstones, which are often found stratigraphically underlying the Krol limestone deposits.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
The Shali Window is a classic tectonic feature where erosion has exposed older Proterozoic carbonate rocks beneath the younger Jutogh thrust sheets, confirming the Lesser Himalayas' complex nappe structure. The Krol Group represents a major Neoproterozoic to Cambrian sedimentary sequence dominated by marine carbonates like limestone and dolomite, which are stratigraphically preceded by the Infra-Krol formation, characterized by dark, carbonaceous shales indicative of a reducing depositional environment. All three statements are factually accurate, reflecting the standard stratigraphic succession and tectonic architecture of the Lesser Himalayan belt.
Consider the following statements regarding Trans-Himalayan Tethyan sedimentary sequences:
1. The Zanskar Synclinorium preserves a nearly continuous stratigraphic record from the Cambrian to the Cretaceous, providing critical data on the evolution of the Neo-Tethys Ocean.
2. The Martoli Group, located in the Kumaon region, constitutes one of the oldest stratigraphic units within the Tethyan sedimentary sequence, dating back to the Neoproterozoic to Cambrian transition.
3. The Tethyan Himalayan sequence represents a thick succession of sedimentary rocks deposited on the northern passive margin of the Indian plate between the Cambrian and Eocene periods.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
All three statements are correct: the Zanskar Synclinorium provides a nearly continuous Paleozoic-Mesozoic record of the Neo-Tethys evolution, the Martoli Group represents the basal Neoproterozoic-Cambrian sedimentary basement of the Tethyan realm in the Kumaon region, and the Tethyan Himalayan sequence is a classic example of a passive margin succession deposited on the northern edge of the Indian plate from the Cambrian until the final closure of the Tethys Ocean in the Eocene.
Consider the following statements regarding Drainage evolution of antecedent river systems:
1. The Indus, Sutlej, and Brahmaputra rivers are classified as antecedent drainage systems because their courses were established prior to the major uplift phases of the Himalayan orogeny.
2. The Indo-Brahma or Siwalik River hypothesis, proposed by Pilgrim in 1919, suggests that a single large river once flowed westward along the southern base of the rising Himalayas before being captured by subsequent drainage.
3. The formation of the Indus drainage basin is linked to the 1960 Indus Waters Treaty, which formalizes the hydrological boundaries of the antecedent rivers flowing through the Ladakh and Karakoram ranges.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as antecedent rivers maintained their courses by eroding the rising Himalayas through deep gorges, predating the mountain formation. Statement 2 is correct because the Indo-Brahma hypothesis posits that a massive longitudinal river once flowed from Assam to the Punjab plains before being fragmented by tectonic shifts. Statement 3 is incorrect because the Indus Waters Treaty is a 1960 water-sharing agreement between India and Pakistan, not a geological or hydrological explanation for the formation of the Indus drainage basin.
Consider the following statements regarding Eolian processes in the high-altitude cold deserts:
1. The formation of ventifacts in the high-altitude deserts of Himachal Pradesh is attributed to intense mechanical weathering, and the 2012 field study confirmed these features are primarily composed of limestone deposits.
2. The Trans-Himalayan region experiences significant sand dune migration, and the 1994 geological survey of the Nubra Valley identified these dunes as being formed by fluvial processes originating from the Shyok River.
3. Aeolian saltation in the Tibetan Plateau is influenced by the diurnal temperature range, and the 2005 climate assessment noted that these processes contribute to the formation of extensive barchan fields in the Zanskar range.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
All three statements are incorrect because they misattribute geological features and historical surveys. Statement 1 is false as ventifacts in the region are primarily formed by wind abrasion on igneous or metamorphic rocks, not limestone; Statement 2 is incorrect because Nubra Valley dunes are primarily aeolian deposits formed by wind action, not fluvial processes from the Shyok River; and Statement 3 is false because the Zanskar range does not host extensive barchan fields, as these are characteristic of flatter desert basins rather than the rugged, high-altitude terrain of the Zanskar region.
Consider the following statements regarding Metamorphic facies of the Higher Himalayan Crystalline:
1. The Vaikrita Group, representing the basal unit of the Higher Himalayan Crystalline, is defined by pre-Himalayan Precambrian metamorphic basement rocks that underwent pervasive blueschist facies metamorphism during the assembly of Gondwanaland.
2. Isotopic dating of zircon grains from the Higher Himalayan Crystalline reveals that the peak amphibolite facies metamorphism occurred during the late Cretaceous period, approximately 85 million years ago, preceding the collision of the Indian and Eurasian plates.
3. Garnet-biotite geothermometry applied to the Higher Himalayan Crystalline samples typically yields peak metamorphic temperatures ranging between 550 and 700 degrees Celsius.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct because garnet-biotite geothermometry in the Higher Himalayan Crystalline (HHC) consistently records peak metamorphic temperatures of 550-700°C, reflecting the Barrovian-type metamorphism associated with crustal thickening. Statement 1 is incorrect because the Vaikrita Group underwent high-grade amphibolite to granulite facies metamorphism during the Cenozoic Himalayan orogeny, not Precambrian blueschist facies. Statement 2 is incorrect because the peak metamorphism of the HHC is syn-collisional, occurring during the Miocene (roughly 20-25 million years ago) due to crustal shortening, rather than the late Cretaceous.
Consider the following statements regarding Paleoclimatic signatures in Himalayan loess deposits:
1. The loess-paleosol sequences found in the Spiti Valley exhibit a high degree of stratigraphic correlation with the Chinese Loess Plateau, and the primary mechanism for dust transport in both regions is the East Asian Summer Monsoon.
2. In the Potwar Plateau, the loess deposits are characterized by high concentrations of volcanic glass shards, which were deposited during the Toba super-eruption approximately 74,000 years ago and serve as a regional marker horizon for the early Holocene.
3. The presence of specific terrestrial gastropod assemblages within the loess layers of the Ladakh region provides secondary evidence for moisture availability and local temperature variations during the Pleistocene.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct because terrestrial gastropod assemblages in Ladakh serve as sensitive bio-indicators, reflecting paleoclimatic fluctuations in moisture and temperature during the Pleistocene. Statement 1 is incorrect because the primary driver for dust transport in the Spiti Valley is the Westerlies, not the East Asian Summer Monsoon, which is the dominant mechanism for the Chinese Loess Plateau. Statement 2 is incorrect because the Toba volcanic ash layer, while present in the Potwar Plateau, dates to approximately 74,000 years ago, which corresponds to the Late Pleistocene, not the early Holocene.
Consider the following statements regarding Periglacial landforms and solifluction processes:
1. The formation of stone stripes in the Ladakh region is primarily attributed to the process of frost heaving and subsequent sorting of debris during seasonal freeze-thaw cycles.
2. The formation of pingos in the Sikkim Himalayas is linked to the presence of artesian groundwater pressure, which elevates the surface layer by up to 10 meters during the winter solstice.
3. Solifluction in the Himalayan high-altitude zones, typically above 4,000 meters, involves the slow downslope movement of water-saturated soil over a frozen subsoil layer known as permafrost.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 3 is correct. Statement 2 is incorrect.
Statement 1 is correct as frost heaving and cryoturbation in high-altitude regions like Ladakh facilitate the sorting of coarse and fine debris into patterned ground, including stone stripes. Statement 3 is correct because solifluction is a characteristic periglacial process where the active layer of soil becomes saturated with meltwater and slides over the impermeable permafrost table, typically occurring above the 4,000-meter threshold in the Himalayas. Statement 2 is incorrect because while pingos are periglacial landforms, they are not a significant feature of the Sikkim Himalayas, and their formation is linked to the expansion of segregated ice lenses rather than simple artesian pressure linked to the winter solstice.
Consider the following statements regarding Structural anatomy of the Main Central Thrust:
1. Field observations in the Kumaon region show that the MCT is characterized by a normal faulting mechanism, which explains the thinning of the crust beneath the high-altitude peaks of Nanda Devi.
2. The MCT is associated with the development of the Main Boundary Thrust, and both structures were formed simultaneously during the initial collision of the Indian and Eurasian plates 50 million years ago.
3. Recent geodetic measurements suggest that the MCT remains the primary locus of active plate convergence, accounting for the majority of the 18 millimeters per year of shortening observed in the central sector.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
The Main Central Thrust (MCT) is a classic thrust fault characterized by compressional, not normal, faulting, and it does not explain crustal thinning beneath Nanda Devi. The MCT (active ~20-25 Ma) and the Main Boundary Thrust (MBT, active ~10-15 Ma) formed sequentially, not simultaneously, during the ongoing India-Eurasia collision. Furthermore, modern geodetic data indicates that the MCT is largely inactive or 'locked' in the central sector, with current plate convergence being accommodated primarily by the Main Himalayan Thrust (MHT) at the base of the crust rather than the MCT.
Consider the following statements regarding Tectonic uplift rates and fluvial incision cycles:
1. Fluvial incision cycles in the Siwalik foothills are periodically interrupted by sediment aggradation events, which are linked to the 100,000-year Milankovitch cycles influencing monsoon intensity.
2. The Sutlej River valley serves as a primary conduit for sediment transport, where the incision rate is calibrated by the 5-million-year-old cooling ages of the underlying metamorphic rocks within the Higher Himalayan Crystalline sequence.
3. Recent stratigraphic studies of the Siwalik Group indicate that the transition from fluvial to lacustrine environments occurred 12 million years ago, marking the final tectonic closure of the Himalayan foreland basin.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is correct because periodic fluctuations in monsoon intensity, driven by 100,000-year orbital Milankovitch cycles, modulate sediment supply and fluvial incision in the Siwaliks. Statement 2 is incorrect because while the Sutlej River is a key conduit, incision rates are calibrated by modern geochronological markers rather than 5-million-year-old cooling ages of the Higher Himalayan Crystalline. Statement 3 is incorrect because the Siwalik Group is characterized by a long-term transition from fluvial to alluvial fan depositional systems, and the foreland basin has not undergone a final tectonic closure 12 million years ago; rather, it remains an active, evolving tectonic feature.
Consider the following statements regarding Orogenic belt seismicity and crustal shortening:
1. The Siwalik range, representing the outermost foothills of the Himalayas, consists of Cenozoic sedimentary deposits that have been deformed by the ongoing southward propagation of the Himalayan deformation front.
2. Geodetic measurements indicate that the Indian Plate is converging with the Eurasian Plate at a rate of about 40 to 50 millimeters per year, contributing to the ongoing orogenic uplift.
3. The 1905 Kangra earthquake occurred along the Main Frontal Thrust (MFT) and resulted in a surface rupture length of 300 kilometers, which defined the seismic gap for the western Himalayan segment.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is incorrect.
Statement 1 is correct as the Siwaliks are composed of molasse deposits formed by the erosion of the rising Himalayas and are currently being folded and faulted by the southward migration of the deformation front. Statement 2 is correct because GPS-based geodetic studies confirm the Indian Plate's steady northward convergence with Eurasia at approximately 40-50 mm/year, driving the ongoing crustal shortening and uplift. Statement 3 is incorrect because, while the 1905 Kangra earthquake was a major seismic event, its surface rupture was significantly shorter than 300 km, and the MFT is the youngest fault system where slip is primarily accommodated by smaller, frequent events rather than a single 300 km rupture.
Consider the following statements regarding Periglacial landforms and solifluction processes:
1. The 1998 study by Hewitt on the Karakoram glaciers identified that solifluction lobes are significant contributors to the sediment supply in high-altitude periglacial valleys.
2. Cryoturbation processes in the Spiti Valley result in the vertical displacement of soil particles, which disrupts the natural soil horizons typically found in temperate regions.
3. Nivation hollows in the Greater Himalayas are formed through the combined action of snow patch persistence and freeze-thaw weathering, often occurring at elevations exceeding 4,500 meters.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Kenneth Hewittâs 1998 research on the Karakoram confirms that solifluction lobes are primary geomorphic agents transporting debris into high-altitude valleys, while cryoturbation in Spiti causes intense frost-churning that physically disrupts soil horizons through cyclic freeze-thaw expansion. Nivation hollows are indeed characteristic features of the Greater Himalayas, typically forming at high altitudes (above 4,500m) where persistent snow patches facilitate mechanical weathering and erosion at the snow-rock interface. All three statements are factually accurate, reflecting established geomorphological processes in the Himalayan periglacial environment.
Consider the following statements regarding Eolian processes in the high-altitude cold deserts:
1. The high-altitude cold desert of Ladakh features yardangs, which are streamlined rock ridges carved by wind abrasion, often oriented parallel to the prevailing north-westerly wind currents.
2. Sand ripples in the high-altitude desert regions of the Himalayas exhibit distinct geometric patterns, and the 2019 satellite imagery study associated these formations with the seasonal deposition of glacial outwash.
3. In the Spiti Valley, the deposition of loess-like sediments is primarily driven by the 'Adhi' winds, which reach peak velocities during the spring months of April and May.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 3 is correct. Statement 2 is incorrect.
Statement 1 is correct as Ladakh's cold desert topography features yardangs formed by the persistent abrasive action of north-westerly winds. Statement 3 is correct because the Spiti Valley experiences significant loess-like sediment deposition during spring, driven by high-velocity 'Adhi' winds that transport fine-grained material. Statement 2 is incorrect because sand ripples in these high-altitude regions are primarily formed by the saltation and surface creep of aeolian processes rather than being linked to seasonal glacial outwash deposition in the manner described by 2019 satellite studies.
Consider the following statements regarding Isostatic equilibrium and Himalayan orogeny:
1. The Hayford-Bowie gravity anomaly studies conducted in the early 20th century provided the first empirical evidence that the Himalayan mass is supported by a rigid lithospheric plate with a uniform thickness of 120 kilometers.
2. The formation of the Siwalik foothills is attributed to the deposition of molasse sediments during the Pliocene, which were subsequently deformed by the Main Boundary Thrust as the Indian plate rotated clockwise by 15 degrees.
3. The Indus-Tsangpo Suture Zone marks the boundary where the Tethys oceanic crust was subducted beneath the Indian Plate, resulting in the formation of the ophiolitic complexes found in the Ladakh region.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because Hayford and Bowie's studies supported the Airy-Heiskanen model of isostasy, which posits that the Himalayas are supported by a deep crustal root (mountain roots) rather than a rigid, uniform lithospheric plate. Statement 2 is incorrect because the Siwaliks were formed by the deposition of molasse sediments derived from the rising Himalayas, but they were deformed by the Main Frontal Thrust (MFT), not the Main Boundary Thrust (MBT), and the Indian plate's movement is characterized by northward convergence rather than a 15-degree clockwise rotation. Statement 3 is incorrect because the Indus-Tsangpo Suture Zone marks the subduction of the Tethys oceanic crust beneath the Eurasian Plate (not the Indian Plate), which led to the collision and the obduction of ophiolitic complexes.
Consider the following statements regarding Stratigraphic classification of the Lesser Himalayas:
1. The Tal Group, overlying the Krol sequence, contains fossiliferous marine sediments that provide critical data for dating the late Mesozoic transition in the Himalayan region.
2. The Jutogh Group consists of high-grade metamorphic rocks such as schists and gneisses, which were thrust over the lower-grade sedimentary sequences of the Lesser Himalayas.
3. The Blaini Formation is recognized for its diamictites, which are widely interpreted by geologists as evidence of a late Neoproterozoic glacial event in the Lesser Himalayan basin.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
All three statements are correct: The Tal Group provides essential paleontological evidence for the Mesozoic transition in the Tethyan realm, while the Jutogh Group represents the crystalline basement or high-grade metamorphic nappe thrust over the Lesser Himalayan sedimentary pile. Furthermore, the Blaini Formation is globally significant for its diamictites, which serve as a stratigraphic marker for the Marinoan glaciation (approx. 635 Ma) during the late Neoproterozoic.
Consider the following statements regarding Drainage evolution of antecedent river systems:
1. Geomorphological evidence from the Zanskar Range indicates that the Indus River has maintained its transverse course through the mountain chain for approximately 5 to 7 million years, predating the final uplift of the Siwaliks.
2. The Sutlej River traverses the Shipki La pass, cutting through the Zanskar and Greater Himalayan ranges, and its deep V-shaped valleys provide evidence of continuous erosional activity during the Pleistocene epoch.
3. The Tsangpo-Brahmaputra river system exhibits a significant 'hairpin bend' near Namcha Barwa, where the river abruptly turns southward to enter the Indian plains, reflecting the structural control of the eastern Himalayan syntax.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
All three statements are correct: Statement 1 is accurate as geochronological studies of the Indus indicate it is an antecedent river that maintained its course during the Himalayan uplift; Statement 2 is correct because the Sutlej cuts through the Zanskar and Greater Himalayas at Shipki La, with its deep V-shaped gorges serving as evidence of ongoing incision during the Pleistocene; Statement 3 is correct as the Brahmaputra's 'hairpin bend' at Namcha Barwa is a classic example of structural control by the eastern Himalayan syntaxis, where the river follows a major tectonic weakness.
Consider the following statements regarding Geomorphological role of the Main Boundary Thrust:
1. Geomorphological analysis of the Siwalik range shows that the MBT acts as the northernmost limit of the Himalayan Frontal Thrust, which defines the drainage patterns of the major antecedent rivers.
2. The Main Boundary Thrust consists of a series of low-angle normal faults that accommodate the crustal extension observed in the Himalayan foothills since the Pliocene epoch.
3. The displacement along the Main Boundary Thrust has resulted in the Siwalik sediments being overridden by the older Precambrian to Paleozoic rocks of the Lesser Himalayan sequence.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct because the Main Boundary Thrust (MBT) is a major south-verging thrust fault where older Lesser Himalayan rocks (Precambrian-Paleozoic) are thrust over the younger Siwalik molasse sediments. Statement 1 is incorrect because the MBT is distinct from the Himalayan Frontal Thrust (HFT), which is the southernmost boundary, and the MBT does not define the drainage of antecedent rivers in the manner described. Statement 2 is incorrect because the MBT is a high-angle reverse (thrust) fault that accommodates crustal shortening and compression due to the ongoing India-Eurasia plate collision, not crustal extension.
Consider the following statements regarding Geomorphological role of the Main Boundary Thrust:
1. The MBT represents the contact zone between the Tethyan Himalayan sequence and the Higher Himalayas, where metamorphic grades shift from greenschist to amphibolite facies.
2. Studies conducted in the Kumaon region identify the MBT as the primary structural feature controlling the formation of the Indus-Tsangpo Suture Zone during the initial collision of the Indian and Eurasian plates.
3. Geological mapping indicates that the MBT is a north-dipping reverse fault system that became significantly active during the Miocene epoch, approximately 10 to 12 million years ago.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct as the Main Boundary Thrust (MBT) is a north-dipping reverse fault that became active during the Miocene (approx. 10-12 Ma) as the Himalayan deformation front migrated southward. Statement 1 is incorrect because the MBT separates the Lesser Himalayas from the Sub-Himalayas (Siwaliks), whereas the contact between the Tethyan and Higher Himalayas is defined by the South Tibetan Detachment System (STDS). Statement 2 is incorrect because the Indus-Tsangpo Suture Zone (ITSZ) represents the initial collision boundary formed much earlier (approx. 50-55 Ma), located far north of the MBT.
Consider the following statements regarding Geomorphological role of the Main Boundary Thrust:
1. Seismic data recorded by the Geological Survey of India suggests that the MBT is a vertical strike-slip fault that facilitates the lateral extrusion of the Tibetan Plateau towards the Bay of Bengal.
2. The Main Boundary Thrust marks the southern limit of the Main Central Thrust (MCT) zone and is responsible for the deposition of the Indo-Gangetic alluvium during the Pleistocene period.
3. The Main Boundary Thrust (MBT) serves as the primary tectonic boundary separating the Lesser Himalayas to the north from the Siwalik Group to the south.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct as the MBT is a major tectonic feature separating the Lesser Himalayas from the Siwalik foothills. Statement 1 is incorrect because the MBT is a low-angle thrust fault, not a vertical strike-slip fault, and the extrusion of the Tibetan Plateau is primarily accommodated by strike-slip faults like the Altyn Tagh. Statement 2 is incorrect because the MBT lies south of the Main Central Thrust (MCT), and the deposition of the Indo-Gangetic alluvium is primarily associated with the foreland basin subsidence caused by the loading of the Himalayan crust, rather than being a direct function of the MBT itself.
Consider the following statements regarding Paleoclimatic signatures in Himalayan loess deposits:
1. Grain-size distribution analysis in the Zanskar valley loess profiles indicates that wind-blown dust deposition was significantly enhanced during the Younger Dryas cold event.
2. The transition from the Last Glacial Maximum (LGM) to the Holocene in the Himalayan loess sequences is marked by a distinct shift in stable carbon isotope values, reflecting changes in C3 and C4 vegetation cover.
3. Luminescence dating, specifically Optically Stimulated Luminescence (OSL), is the preferred geochronological technique for establishing the depositional chronology of loess units younger than 200,000 years in the region.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
Statement 1 is correct as grain-size analysis in Zanskar loess confirms increased aeolian activity and aridity during the Younger Dryas (c. 12.9-11.7 ka). Statement 2 is correct because stable carbon isotopes (δ13C) in these deposits track shifts in the C3/C4 plant ratio, which serves as a proxy for monsoon intensity and temperature fluctuations during the LGM-Holocene transition. Statement 3 is correct because OSL is the standard geochronological tool for dating quartz or feldspar grains in loess, providing reliable age estimates for the late Quaternary period (up to ~200,000 years) by measuring the time elapsed since the last exposure to sunlight.
Consider the following statements regarding Trans-Himalayan Tethyan sedimentary sequences:
1. The Garhwal Group represents the primary sedimentary basin for the deposition of the Tethyan sequences, with its base defined by the widespread occurrence of Precambrian glacial tillites known as the Blaini Formation.
2. The Kioto Limestone, a prominent formation in the Tethyan Himalaya, is primarily composed of deep-marine radiolarian cherts deposited during the peak of the Cretaceous oceanic expansion.
3. The Haimanta Group in the Spiti region contains extensive volcanic basalt flows that date to the Permian period, marking the initial rifting phase of the Indian plate from Gondwanaland.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is incorrect. Statement 2 is incorrect. Statement 3 is incorrect.
Statement 1 is incorrect because the Garhwal Group belongs to the Lesser Himalaya, not the Tethyan sequence, and the Blaini Formation is associated with the Lesser Himalayan stratigraphy. Statement 2 is incorrect as the Kioto Limestone is a massive, shallow-marine carbonate platform deposit of the Triassic-Jurassic period, not deep-marine Cretaceous cherts. Statement 3 is incorrect because the Haimanta Group represents Precambrian to Cambrian siliciclastic sediments, whereas the Permian rifting of Gondwanaland is marked by the Panjal Traps volcanic sequence.
Consider the following statements regarding Periglacial landforms and solifluction processes:
1. Rock glaciers in the Pir Panjal range are classified as periglacial landforms that move at a velocity of 5 meters per year, driven by the internal deformation of ice-rich permafrost.
2. The 1974 Geological Survey of India report on the Himachal periglacial zone describes thermokarst topography as the dominant landform feature resulting from the melting of massive subterranean ice lenses.
3. Patterned ground, including polygons and circles, is observed in the Zanskar Range where the active layer thickness varies between 0.5 and 1.5 meters during the summer months.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct as the Zanskar Range exhibits active periglacial processes where seasonal freeze-thaw cycles create patterned ground within an active layer typically ranging from 0.5 to 1.5 meters. Statement 1 is incorrect because while rock glaciers are periglacial, their movement is generally much slower, typically measured in centimeters rather than 5 meters per year. Statement 2 is incorrect because thermokarst topography is primarily associated with Arctic regions containing massive ground ice, whereas the Himachal periglacial zone is characterized by frost weathering and solifluction rather than widespread thermokarst development.
Consider the following statements regarding Geochemical weathering and carbon sequestration rates:
1. The tectonic uplift of the Himalayan range exposes silicate minerals like calcium and magnesium silicates to chemical weathering, which facilitates the sequestration of atmospheric carbon dioxide.
2. The high relief and intense monsoon precipitation in the Himalayas increase the physical erosion rate, which in turn exposes fresh mineral surfaces for continued chemical weathering.
3. Chemical weathering of silicate rocks in the Himalayan region consumes approximately 0.03 to 0.06 gigatonnes of carbon per year through the formation of bicarbonate ions.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
The Himalayan uplift accelerates the chemical weathering of silicate minerals, a process that acts as a long-term carbon sink by converting atmospheric CO2 into dissolved bicarbonate ions that are transported to oceans. High relief and monsoon-driven erosion continuously strip away weathered soil, exposing fresh mineral surfaces to sustain this chemical reaction, which is estimated to sequester approximately 0.03 to 0.06 gigatonnes of carbon annually. All three statements are factually accurate, reflecting the established geological consensus on the role of the Himalayas in the global carbon cycle.
Consider the following statements regarding Glacial geomorphology and moraine-dammed lakes:
1. The Bhutanese glacial lake inventory identifies the Lugge Tsho as a high-risk site, which underwent a controlled drainage operation in 1974 following the catastrophic outburst event that occurred in the Lunana region.
2. Lateral moraines are formed by the deposition of unsorted glacial till along the sides of a glacier, and the formation of the Pangong Tso is attributed to the damming of a valley by these specific glacial deposits during the late Pleistocene.
3. The 2013 Kedarnath disaster in India was significantly exacerbated by the breach of the Chorabari Tal, a moraine-dammed lake located at an elevation of 3,895 meters above sea level.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 3 is correct. Statement 1 is incorrect. Statement 2 is incorrect.
Statement 3 is correct because the 2013 Kedarnath disaster was triggered by the breach of Chorabari Tal, a moraine-dammed lake, due to extreme rainfall. Statement 1 is incorrect because the catastrophic outburst of Lugge Tsho occurred in 1994, not 1974, and the subsequent mitigation efforts were initiated much later. Statement 2 is incorrect because while lateral moraines are correctly defined, Pangong Tso is a tectonic lake formed by the Indian Plate's collision with the Eurasian Plate, not by glacial moraine damming.
Consider the following statements regarding Geodynamic implications of the Himalayan-Tibetan Plateau system:
1. The ongoing convergence between the Indian and Eurasian plates occurs at a rate of approximately 40 to 50 millimeters per year.
2. The Tibetan Plateau maintains an average elevation exceeding 4,500 meters, a result of crustal thickening that began approximately 50 million years ago.
3. The Main Boundary Thrust (MBT) separates the Lesser Himalayas from the Sub-Himalayan Siwalik range, reflecting significant crustal shortening.
How many of the statements given above are correct?
- Only one
- Only two
- All three
- None
Explanation: Statement 1 is correct. Statement 2 is correct. Statement 3 is correct.
The Indian plate continues to converge with the Eurasian plate at a rate of 40-50 mm/year, driving the ongoing uplift of the Himalayas. The Tibetan Plateau's average elevation exceeds 4,500 meters due to crustal thickening initiated by the continental collision approximately 50 million years ago during the Eocene epoch. The Main Boundary Thrust (MBT) is a major geological fault that marks the boundary between the Lesser Himalayas and the Siwalik range, serving as a primary site for crustal shortening and seismic activity in the region.