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Q91. Which one of the magnitude scales given below DOES NOT saturate while estimating size of earthquakes?
The correct answer is Moment magnitude scale (MW). When tracking gigantic earthquakes, older scales like the Local (Richter), Body wave, and Surface wave scales 'saturate'—meaning their math maxes out and they cannot accurately measure anything past a certain size (like a thermometer that only goes up to 100 degrees). The Moment magnitude scale is based on the actual physical energy and size of the broken rock, so it never maxes out, making it the only correct choice for massive quakes.
Q92. A limestone contains lime mud and around 25% allochems, which are separated from each other. The name of the rock as per Dunham’s classification is
The correct answer is wackestone. According to Dunham's classification of carbonate rocks, if a limestone is mostly composed of fine mud but contains between 10% and 50% larger grains (allochems) that are floating freely in the mud without touching each other (mud-supported), it is strictly defined as a 'Wackestone'. A mudstone has less than 10% grains. A packstone is grain-supported, and a grainstone lacks mud entirely.
Q93. Among the following rocks, the one with highest metamorphic grade is
The correct answer is gneiss. Metamorphic 'grade' means how much heat and pressure a rock endured. 'Phyllite' and 'chlorite schist' are baked at very low, weak temperatures. 'Glaucophane schist' (blueschist) is smashed by high pressure but stays very cold. 'Gneiss', however, is baked at incredibly high temperatures and pressures deep in the Earth, causing its minerals to melt and separate into distinct tiger-stripes. This makes it the highest grade.
Q94. Among the following, the tungsten-bearing mineral is
The correct answer is scheelite. Scheelite is a heavy, famously fluorescent mineral that is scientifically an ore of Calcium Tungstate, making it one of the world's primary sources of the rare metal Tungsten. Bornite is mined for copper. Cassiterite is famously mined for tin. Greenockite is a rare, yellow mineral containing cadmium. Therefore, scheelite is the only correct answer.
Q95. Bituminous coal deposits in India occur in which one of the following formations?
The correct answer is Barakar Formation. The Barakar Formation, located in eastern India, is legendary for holding the country's thickest, richest, and most economically vital seams of black bituminous coal. The 'Barren Measures', appropriately named, are mostly barren of coal. Cuddalore holds brown lignite, not black bituminous coal. The Naredi Formation is a marine deposit in Kutch with no massive coal swamps.
Q96. Choose the CORRECT match between items in Group I with the items in Group II. P. Polarity zone 1. Biostratigraphy Q. Formation 2. Chronostratigraphy R. Biozone 3. Magnetostratigraphy S. Epoch 4. Lithostratigraphy
The correct answer is P-3; Q-4; R-1; S-2. Geologists use different rules to classify rocks. A 'Polarity zone' relies on the Earth's magnetic flips (Magnetostratigraphy). A 'Formation' is purely based on the physical type of rock like sandstone or shale (Lithostratigraphy). A 'Biozone' uses the specific fossils trapped inside (Biostratigraphy). An 'Epoch' is a measurement of pure, absolute time (Chronostratigraphy). Option C is the only one that links every term correctly.
Q97. Choose the CORRECT pair of crystal systems that represents the optic orientation shown in the figure.
The correct answer is Orthorhombic - Monoclinic. The visual diagrams display how optical vibration axes (X, Y, Z) align with crystallographic axes (a, b, c). In the first diagram, the optical axes perfectly coincide with all three crystallographic axes, which is the strict, defining optical rule for the Orthorhombic system. In the second diagram, only one optical axis (Y) aligns with a crystallographic axis (b), while the others are slanted. This partial misalignment strictly defines the Monoclinic system.
Q98. Choose the CORRECT sequence of older to younger formations in the stratigraphy of the Cuddapah Supergroup
The correct answer is Gulcheru-Vempalle-Pulivendla-Tadpatri. Stratigraphy is the study of rock layers, reading them like pages in a history book from oldest (bottom) to youngest (top). In the famous ancient Cuddapah basin in India, geologists have mapped the rock sequence. The very bottom, oldest layer is the Gulcheru quartzite. On top of that is the Vempalle dolomite, followed by the Pulivendla quartzite, and finally capped by the youngest Tadpatri shale.
Q99. Find the CORRECT statement out of the following.
The correct answer is Prod mark is found at the bottom of a bed. A 'prod mark' is a type of tool mark created when a stick or shell is violently jammed into soft mud by a flowing current, leaving a gouge that fills with overlying sand, preserving it strictly on the bottom of the upper bed. Convolute laminae form by soft-sediment deformation, not drying (desiccation). Load casts are deformational, not erosional. Turbidites form in deep water far below wave action.
Q100. Identify the plant fossil from the following list.
The correct answer is Glossopteris. Glossopteris is a highly famous extinct genus of seed ferns that dominated the ancient supercontinent of Gondwana. Its leaf fossils are a critical piece of evidence for continental drift. Fenestella is a marine bryozoan, Productus is a brachiopod, and Cidaris is a sea urchin, meaning they are all animal fossils, not plants.