Q10. The Chota Nagpur Plateau is primarily composed of which rocks?
[WBCS Preliminary Examination (2018)]
- (A) Sandstone, limestone and shale
- (B) Granite, limestone and dolomite
- (C) Ancient granite and gneiss
- (D) Gondwana coal, sandstone and limestone
Answer: (C) Ancient granite and gneiss
Explanation: The Chota Nagpur basement chiefly consists of ancient crystalline rocks, including granite and gneiss, although younger Gondwana sedimentary basins also occur. This distinction explains why the region contains both long-exposed Precambrian uplands and major coal-bearing valleys.
Q9. Which Rajasthan hills are an extension of the Vindhyan ranges?
[RPSC RAS Preliminary Examination (2018)]
- (A) Mukandara Hills
- (B) Dora mountain
- (C) Alwar Hills
- (D) Girwa Hills
Answer: (A) Mukandara Hills
Explanation: The Mukandara Hills belong to the southeastern Rajasthan upland belt associated with the Vindhyan system. Their location in the Hadoti region distinguishes them from the Aravalli-related Alwar uplands and other locally named hill groups.
Q8. Which rock system supplies more than 90 percent of India’s coal?
[UPPSC Civil Services Preliminary Examination (2017)]
- (A) Vindhyan system
- (B) Dharwar system
- (C) Tertiary system
- (D) Gondwana system
Answer: (D) Gondwana system
Explanation: Gondwana rocks contain India’s principal coal-bearing formations, notably within the Damodar, Son, Mahanadi and Godavari basins. Their plant-rich sedimentary successions formed long after much of India’s crystalline basement and provide the bulk of conventional coal deposits.
Q7. The Deccan Traps of western India mainly consist of which materials?
[SSC Stenographer (12 September 2017, Shift 2)]
- (A) Volcanic rocks including basaltic lava
- (B) Loose sand and pebbles
- (C) Deep-seated granite and gabbro only
- (D) None of these
Answer: (A) Volcanic rocks including basaltic lava
Explanation: Repeated eruptions of low-viscosity basaltic lava created extensive nearly horizontal sheets in western India. Cooling of successive flows produced the Deccan Traps and their stair-step relief, which contrasts with loose sediment deposits or exclusively intrusive granite.
Q6. Which of these Indian rock systems is the youngest?
[UPPSC Civil Services Preliminary Examination (2016)]
- (A) Vindhyan
- (B) Cuddapah
- (C) Dharwar
- (D) Gondwana
Answer: (D) Gondwana
Explanation: Gondwana sediments are substantially younger than the ancient Dharwar, Cuddapah and Vindhyan systems. They accumulated in continental basins during late Paleozoic and Mesozoic intervals and became particularly important because of their coal-bearing layers.
Q5. Which is the correct geological-system sequence from oldest to youngest in the given choices?
[UPSC CAPF Assistant Commandants (26 June 2016)]
- (A) Dharwar–Aravalli–Vindhyan–Cuddapah
- (B) Aravalli–Dharwar–Cuddapah–Vindhyan
- (C) Vindhyan–Dharwar–Aravalli–Cuddapah
- (D) Cuddapah–Vindhyan–Dharwar–Aravalli
Answer: (B) Aravalli–Dharwar–Cuddapah–Vindhyan
Explanation: The examination’s keyed traditional ordering is Aravalli, Dharwar, Cuddapah and Vindhyan. Geological ages can overlap within these broad historical labels, but the question tests the conventional sequence as expressed in the supplied options.
Q4. Which river flows through a rift valley?
[CGPSC Preliminary Examination, General Studies (2016)]
- (A) Kaveri
- (B) Yamuna
- (C) Son
- (D) Tapi
Answer: (D) Tapi
Explanation: The Tapi flows westward through a structurally controlled valley associated with faulting in central India. Along with the Narmada, it contrasts with the eastward drainage of most large peninsular rivers, showing how tectonic lineaments guide drainage patterns.
Q3. Which rock is least likely to contain fossils?
[Jharkhand Civil Services Preliminary Examination (2015)]
- (A) Conglomerate
- (B) Granite
- (C) Shale
- (D) Sandstone
Answer: (B) Granite
Explanation: Granite crystallises from hot magma, making preservation of original organic remains highly unlikely. Conglomerate, shale and sandstone are sedimentary rocks that can bury and preserve fossils, allowing reconstruction of ancient organisms and geological environments.
Q2. Which statements about India’s Peninsular Plateau are correct? 1. Southern plateau mainly granite and gneiss. 2. Deccan lava plateau has horizontal lava sheets. 3. Malwa forms the eastern flank. 4. Narmada–Tapi trough system lies in central India.
[UPSC CAPF Assistant Commandants (13 July 2014)]
- (A) 1, 2, 3 and 4
- (B) 1, 2 and 4
- (C) 1 and 2 only
- (D) 4 only
Answer: (B) 1, 2 and 4
Explanation: Ancient granite and gneiss underlie much of the southern plateau, and Deccan flows are broadly layered. The Narmada–Tapi structural trough system is important; Malwa, however, lies on the western rather than eastern side of the Central Highlands.
Q1. Why are the Gondwana rocks considered among India’s most important rock systems?
[UPSC CSE Preliminary Examination (2010)]
- (A) They hold over 90 percent of limestone reserves
- (B) They hold over 90 percent of coal reserves
- (C) They underlie over 90 percent of black cotton soils
- (D) None of these
Answer: (B) They hold over 90 percent of coal reserves
Explanation: Gondwana sedimentary basins host the great majority of India’s major coal reserves. Buried ancient vegetation accumulated in tectonic depressions and underwent coalification. By comparison, black soil is closely associated with weathered Deccan basalt rather than Gondwana strata.
