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Q61. Which one of the following Gondwana flora is a seed?
The correct answer is Cordaicarpus. When studying ancient plant fossils from the Gondwana supercontinent, 'Cordaicarpus' specifically refers to the fossilized seed of an extinct plant. 'Dadoxylon' refers to fossilized wood, while 'Taeniopteris' and 'Palaeovittaria' refer to fossilized leaves, making them incorrect choices for a seed.
Q62. Which one of the following is a gently sloping (< 10) volcanic landform resulting from eruption of basaltic lava?
The correct answer is Shield volcano. Basaltic lava is very runny. When it erupts, it spreads out far and wide before cooling, creating a broad volcano with very gentle slopes. Composite volcanoes are steep and form from thicker, explosive lava. Lava domes are small, steep mounds of thick lava. A caldera is a sunken crater formed when a volcano collapses, making them all incorrect.
Q63. Which one of the following is NOT a sediment-gravity flow?
The correct answer is Hypopycnal flow. A 'hypopycnal flow' occurs when fresh, muddy river water is lighter than the salty ocean water, so it floats in a plume on the top surface rather than flowing along the bottom due to gravity. Debris flows, mudflows, and turbidity currents are all examples of heavy mixtures flowing downhill directly pulled by gravity, making them incorrect answers for this 'NOT' question.
Q64. Which one of the following mineral deposits is NOT related to the mining for energy production?
The correct answer is Rampura-Agucha. Rampura-Agucha is a massive zinc and lead mine. Because zinc and lead are used for industry and batteries, not as fuel to generate energy, it is the odd one out. Narwapahar, Jaduguda, and Turamdih are all famous uranium mines in India, making them directly tied to energy production and therefore incorrect answers.
Q65. Which one of the following minerals is NOT a framework silicate?
The correct answer is Chlorite. Silicate minerals are built from tiny silicon-oxygen pyramids. In 'framework' silicates (like Quartz, Feldspar, and Zeolite), all the corners of these pyramids link together to form a strong 3D grid, meaning those options are true framework silicates. Chlorite, however, is a 'sheet' silicate, where the pyramids link into flat layers, so it is the correct answer.
Q66. Which one of the following options is the CORRECT sequence of seismic waves in order of arrival time recorded on a seismogram after an earthquake?
The correct answer is P-waves, S-waves, Love waves, Rayleigh waves. Primary (P) waves are the fastest and arrive first. Secondary (S) waves are slower and arrive next. These are followed by surface waves. Among surface waves, Love waves generally travel slightly faster than Rayleigh waves, making Rayleigh waves the very last to be recorded. This makes all other listed sequences chronologically incorrect because they place Love and Rayleigh surface waves out of order.
Q67. Which one of the following processes is NOT a mechanism for bedload sediment transport in a river channel?
The correct answer is Cavitation. 'Bedload' refers to the heavy rocks and sand that travel along the very bottom of a river. Cavitation is a completely different process where fast-flowing water creates tiny vacuum bubbles that implode and physically chip away at solid rock; it is an erosion mechanism, not a way to transport sediment. Sliding, rolling, and saltation are the actual transport methods, making them incorrect choices for this 'NOT' question.
Q68. Which one of the following relationships between the topographic contour value (t) and the stratum contour value (x) of a bed must be TRUE for an outcrop of the bed to occur on the topographic surface?
The correct answer is t = x. An outcrop is simply where an underground rock layer breaks through and becomes visible on the Earth's surface. A topographic contour (t) measures the elevation of the ground, and a stratum contour (x) measures the elevation of the rock layer. For the rock to be exactly on the surface, its elevation must perfectly match the ground's elevation. If it was double or triple, the math would indicate deep burial or suspension in the air, so the other options are wrong.
Q69. Which one of the following statements about the hydrological cycle is CORRECT?
The correct answer is Groundwater flows in curved and concave-upward path. In large underground water systems, physics and pressure dictate that groundwater moves deep underground in sweeping, curved, concave-upward paths before discharging into rivers. Option A is wrong because glaciers hold the most freshwater. Option B is wrong because the ground can simply fill up entirely to cause runoff, regardless of rain speed. Option C is wrong because a huge amount of rain evaporates back into the sky.
Q70. Which one of the following statements is CORRECT?
The correct answer is Banded Iron Formations are of chemogenic origin. 'Chemogenic' means rocks formed by chemicals precipitating directly out of water, which perfectly describes ancient Banded Iron Formations. Porphyry deposits are volcanic (not sedimentary). Quartz-pebble gold is usually a placer deposit (carried by rivers), not from supergene weathering. Fullerene is a carbon molecule, not a residual geological deposit. Thus, the other options are incorrect.