List of top Geology Questions

An aquifer has a surface area of 100 km². With no recharge, assume that pumping out \(2 \times 10^{7}\) m³ of ground water resulted in a drop of the water table by 6 m. If the aquifer has a specific retention of 15%, then the porosity of the aquifer is % (rounded off to one decimal place).

The bore hole distribution of a massive sulphide deposit represented in the form of an equilateral triangular pattern is given below. If the average thickness of the ore body is 30 m, the tonnage in the shaded area is million tons (rounded off to two decimal places).

[Use: Bulk density of ore body = 4400 kg/m³]

An oblique-slip normal fault dipping \(60^{\circ}\)E shows a net slip of 100 m. If the net slip vector has a pitch of \(30^{\circ}\), then the heave of the fault is m (answer in integer).

A mafic magma with 'Sr' concentration of 400 ppm has undergone 60% fractional crystallization. If 'Sr' is incompatible in the mineral assemblage that crystallizes from the magma with a bulk distribution coefficient of 0.2, the concentration of 'Sr' in the residual liquid is ppm (rounded off to nearest integer).

Which of the following is/are diagenetic process(es)?

The Fe-Mg exchange reaction between olivine and spinel is the following:

\[ \mathrm{Mg_2SiO_4 + 2FeAl_2O_4 \rightleftharpoons Fe_2SiO_4 + 2MgAl_2O_4} \]
(Forsterite) (Fe-spinel) (Fayalite) (Mg-spinel)

Assuming ideal solid solutions, the temperature of equilibration between olivine and spinel using the following data is \(^{\circ}\text{C}\) (round off to nearest integer).

[Assume that \(\Delta H_r^{0}\) and \(\Delta S_r^{0}\) are independent of P and T, and \(K_d\) is independent of P]

\[ K_d = \left[\frac{(X_{Fe}^{Ol})(X_{Mg}^{Sp})}{(X_{Mg}^{Ol})(X_{Fe}^{Sp})}\right]^2 \]

ΔH0r (kJ/mol)	ΔS0r (J/mol.K)	Kd	R (J/mol.K)
-10.91	-3.90	3.024	8.314

The figure below shows an infinite-slope model. If \(\tau\) and SS denote the driving shear stress and the resisting shear strength, respectively, then \(\tau\) along the failure plane is \(\times 10^3\) kg/ms\(^2\) (round off to two decimal places).
[Use: \(d = 2\) m; \(\rho_{soil} = 2.0\) g/cm\(^3\); \(g = 9.8\) m/s\(^2\)]

Which of the following is/are diagnostic morphological feature(s) of brachiopods?

The given schematic diagram shows different stages of development of S\(_2\) foliation after the formation of S\(_1\) foliation. Which of the following statements CORRECTLY interpret(s) the relationships of porphyroblasts W, X, Y and Z with the matrix?

Choose the marked climate zones P, Q, R and S in the figure CORRECTLY from the following options.

In remote sensing, the parameter(s) that can be estimated in the Thermal Infrared region (3 - 14 \(\mu\)m) is/are

Match the mineral names in Group I with corresponding space groups in Group II.

A hydrothermal solution contains dissolved ions of Ca\(^{2+}\) and SO\(_4^{2-}\). If the Saturation Index (SI) of the solution is negative, which of the following statements is/are CORRECT if gypsum is added to the solution?

Which of the following statements CORRECTLY describe(s) a parallel fold?

Which one of the following chrons of Neogene and Quaternary geomagnetic polarity time scale is arranged in the order from oldest to youngest?

The ternary diagram given below shows phase relations for the Anorthite-Diopside-Forsterite system at 1 bar pressure. Broken lines represent isotherms with temperature in °C. If 'P' is the initial melt composition, which one of the following is the CORRECT sequence of crystallization assuming equilibrium between crystal and melt?

Match the minerals in Group I with the corresponding elements in Group II.

Match the stratigraphic Formations in Group I with the corresponding Geologic Periods in Group II.

Accumulation of which one of the following minerals can explain positive Eu and positive Sr anomalies in the primitive mantle-normalized multielement pattern of an igneous rock?

A sandstone bed has an orientation of 360/45W. If the true thickness of the bed is 50 m, the width of the outcrop exposed on a flat surface is _________ m (rounded off to one decimal place).

Two tectonic plates, P and Q, move in opposite directions along a transform fault boundary. If the plate velocity of P is 8 cm/year and of Q is 6 cm/year with respect to a fixed reference frame, the relative velocity between P and Q is _______ cm/year (answer in integer).

The given table shows modal volume percentage of quartz, alkali feldspar and plagioclase in coarse-grained rocks, X and Y. Which of the following rock names of X and Y are CORRECT according to the IUGS classification?

For a chemical system with 5 phases at the invariant point, the number of possible univariant reactions in pressure-temperature space is ____ (answer in integer).

A mineral under crossed nicols displays second order greenish-yellow (\(M = 740\) nm) interference colour. On introduction of a gypsum plate (\(A = 550\) nm) along the length of the mineral orientation, first order grey interference colour is displayed. The net retardation is _________ nm (answer in integer).

Which one of the following mineral reactions will result in the formation of a diagnostic granulite facies assemblage during regional metamorphism of a pelite?