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Q41. Mud-supported limestone containing greater than 10% allochems (grains) is called:
According to Dunham's classification: Mud-supported <10% grains = Mudstone; >10% grains = Wackestone. Grain-supported = Packstone.
Q42. In a typical coal mine area affected by acid mine drainage, which one of the following acids will be dominant?
Acid mine drainage is caused by the oxidation of sulfide minerals (like Pyrite, FeS2), which produces Sulphuric Acid (H2SO4).
Q43. Acoustic impedance is the ___ of density and velocity.
Acoustic Impedance (Z) is defined as the product of density (rho) and seismic velocity (V): Z = rho * V.
Q44. Which one of the following planets has the highest bulk density?
Among the options, Venus (5.24 g/cc) is the densest. Earth is the densest overall (~5.5 g/cc) but is not listed. Gas giants like Jupiter and Saturn have very low densities (<1.4 g/cc).
Q45. At 500m depth, Max Horizontal Stress = 20 MPa, Vertical Stress = 13.5 MPa, Min Horizontal Stress = 8 MPa. This stress field leads to which fault?
Anderson's Theory: Strike-slip faults form when the Vertical Stress is the intermediate stress (Sigma 2). Here, 20 (S1) > 13.5 (S2) > 8 (S3).
Q46. A clastic rock dominantly composed of feldspar grains is:
Arkose is a sandstone containing at least 25% feldspar. Arenite is pure quartz; Greywacke has a muddy matrix; Shale is fine-grained clay.
Q47. The maximum amount of hydrogen (dry mineral matter free basis) in bituminous-anthracite is:
As coal rank increases to Anthracite, volatiles (including Hydrogen) decrease significantly, typically dropping below 4-5%.
Q48. From the surface to the Earth's interior, the velocity of P-wave decreases and the material density increases at the boundary between:
At the Gutenberg discontinuity (Mantle-Core boundary), P-wave velocity drops sharply because the Outer Core is liquid. Density increases due to the compositional change to Iron/Nickel.
Q49. Correct rock-texture pairs
Basalt-Porphyritic Porphyroblastic-Metamorphic rocks
Q50. In Gondwanaland reconstructions, much of the present west coast of India is placed adjacent to:
Before the breakup of Gondwana, Madagascar was attached to the western margin of the Indian subcontinent.