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Q131. In clastic sediments, the correct order of decreasing grain size is
The correct answer is Cobble > granule > silt > clay. Geologists strictly categorize dirt and rocks by size using the Udden-Wentworth scale. The sequence from largest to smallest is: Boulder, Cobble, Pebble, Granule, Sand, Silt, and finally Clay. Looking at the options, only Option C correctly lists the items in a continuously descending order without mixing up large rocks and fine muds.
Q132. In the given profile section, P, Q, R, S and T are sedimentary rocks. Identify the type of unconformity in the sedimentary sequence. (Image shows tilted beds P, Q, R underneath flat horizontal beds S, T)
The correct answer is Angular unconformity. An unconformity is a missing gap in rock history. In the provided diagram, the older bottom rocks (P, Q, and R) were violently tilted at an angle by tectonic forces and then sheared flat by erosion. Millions of years later, brand new rocks (S and T) were laid down perfectly flat on top. This stark, visible difference in angle between the top and bottom layers is universally called an 'Angular unconformity'.
Q133. Mammalian fossils are commonly found in
The correct answer is Siwalik Group. The Siwalik Group is a famous, thick sequence of sedimentary rocks running along the foothills of the Himalayas. Formed relatively recently during the Neogene period, these rocks are globally renowned for containing an incredibly rich and diverse collection of ancient mammalian fossils (like extinct elephants, apes, and horses). The other groups are mostly older marine or dinosaur-era deposits.
Q134. Match the landform in Group I with the corresponding geological process in Group II. P. Cinder Cone 1. Eolian; Q. Ox-bow lake 2. Glacial; R. Draas 3. Volcanic; S. Drumlin 4. Fluvial
The correct answer is P-3 Q-4 R-1 S-2. A Cinder Cone is a classic 'Volcanic' eruption mound. An Ox-bow lake is a cut-off river bend, making it 'Fluvial'. 'Draas' are massive, wind-blown sand seas found in deserts, categorizing them as 'Eolian'. Finally, a Drumlin is a streamlined hill of dirt scraped and dumped by moving ice, making it strictly 'Glacial'.
Q135. Match the mineral/metal deposit in Group I with the corresponding Indian occurrence in Group II. P. Diamond Q. Iron; R. Fluorite S. Copper 1. Malanjkhand; 2. Wajrakarur 3. Dalli Rajhara; 4. Ambadongar
The correct answer is P-2 Q-3 R-4 S-1. In Indian economic geology, these locations are legendary. Wajrakarur (Andhra Pradesh) is famous for its diamond-bearing kimberlite pipes. Dalli Rajhara (Chhattisgarh) is a massive iron ore mining complex. Ambadongar (Gujarat) contains vast deposits of fluorite. Finally, Malanjkhand (Madhya Pradesh) is recognized as the single largest copper mining project in all of India.
Q136. Match the name of granitoid in Group I with the corresponding Craton in Group II. P. Closepet 1. Singhbhum; Q. Berach 2. Bastar; R. Dongargarh 3. Dharwar; S. Mayurbhanj 4. Aravalli
The correct answer is P-3 Q-4 R-2 S-1. In Indian geology, cratons are identified by massive granite bodies. The massive Closepet Granite perfectly bisects the Dharwar Craton in the south. The ancient Berach Granite is rooted in the Aravalli Craton. The Dongargarh Granite is a prominent feature of the Bastar Craton. Finally, the Mayurbhanj Granite is located within the eastern Singhbhum Craton.
Q137. Match the primary sedimentary structure in Group I with the corresponding process of formation in Group II. P. Asymmetric ripples Q. Dish and pillar R. Flute cast S. Wavy bedding 1. Water escape;2. Bed load transportation of sediments 3. Deposition from alternate traction and suspension load; ; 4. Scouring by turbulent eddy
The correct answer is P-2 Q-1 R-4 S-3. Asymmetric ripples are pushed along the bottom by one-way river currents (Bed load transportation). Dish and pillar structures form when trapped water violently erupts upward through soft sand (Water escape). Flute casts are gouged into mud by swirling underwater vortexes (Scouring by turbulent eddy). Wavy bedding requires switching between flowing currents pushing sand (traction) and still water dropping mud (suspension).
Q138. Match the seismic discontinuity in Group I with their occurrence in Earth’s interior in Group II. P. Conrad 1. Between lower mantle and outer core; Q. Mohorovičić 2. Between crust and upper mantle; R. Gutenberg 3. Between inner and outer core; S. Lehmann 4. Between lower and upper crust
The correct answer is P-4 Q-2 R-1 S-3. The Conrad discontinuity separates the light upper crust from the heavier lower crust. The famous Mohorovičić (Moho) completely separates the crust from the mantle. The Gutenberg discontinuity is the massive drop-off where the solid rocky mantle meets the liquid iron outer core. The Lehmann discontinuity marks the boundary where the liquid outer core finally freezes into the solid inner core.
Q139. Match the twinning in Group I with the corresponding mineral in Group II. P. Cross-hatched 1. Plagioclase; Q. Carlsbad 2. Microcline; R. Polysynthetic 3. Sanidine; S. Brazil 4. Quartz
The correct answer is P-2 Q-3 R-1 S-4. In optical mineralogy, certain crystals grow with iconic, diagnostic 'twin' patterns. Microcline feldspar universally shows a beautiful, plaid-like 'cross-hatched' (tartan) twinning. Sanidine frequently exhibits a simple 'Carlsbad' twin. Plagioclase feldspar is legendary for its multiple striped 'polysynthetic' twins. Finally, Quartz crystals are famous for their optical 'Brazil' twinning.
Q140. Randomly oriented ore-bearing veinlets in a mass of rock are known as
The correct answer is stockworks. In economic geology, 'stockworks' are complex 3D networks of hundreds of tiny, completely randomly oriented, intersecting mineral veinlets that permeate a host rock. 'En echelon' veins form in neat, parallel, staggered steps. 'Sheeted' veins are closely spaced parallel cracks. A 'lode' is a distinct, massive single vein of ore.