List of top Questions asked in IIT JAM GG

Match the mineral deposits in Group I with their Indian occurrences in Group II.
\[ \begin{array}{|l|l|} \hline \textbf{Group I} & \textbf{Group II} \\ \hline P. \ \text{Chromite} & 1. \ \text{Jhamarkotra, Rajasthan} \\ Q. \ \text{Magnesite} & 2. \ \text{Gudur, Andhra Pradesh} \\ R. \ \text{Mica} & 3. \ \text{Byrapur, Karnataka} \\ S. \ \text{Phosphorite} & 4. \ \text{Chalk Hills, Tamil Nadu} \\ \hline \end{array} \]

The top surface of a coal seam is exposed at 150 m contour level on a hill top at location A. The same surface of the seam is also exposed on a river bed at location B at the 50 m contour level. The aerial distance A-B is 1 km. The amount of dip of the coal seam along A-B is (degree). (Give answer in one decimal place).

A fault surface in an outcrop has slickenside lineation whose pitch is 30°. The horizontal slip on the fault is 1.25 m, as determined from displaced vein. The net slip on the fault is (give answer in two decimal places).

In an outcrop, we find a Belemnite fossil broken into five rectangular pieces (boudins) of equal size. Long dimension of each boudin is 1.35 cm. Gap between adjacent boudins in all cases is 0.25 cm. Note that the long dimensions of boudins are perfectly aligned. The % elongation is (give answer in one decimal place).

A horizontal cylindrical ore body (diameter = 20 m, length = 200 m) has 5% metal content and density of 3500 kg/m³. The reserve of the ore body is (give answer in million tons).

A drainage basin of fourth order covers an area of 40 sq. km. Within the basin, total length of 1st order drainage is 12.5 km, 2nd order drainage is 8.8 km, 3rd order drainage is 4.7 km and 4th order drainage is 4.0 km. The drainage density of the basin is (give answer in two decimal places).

Consider a granulite facies metamorphic rock with peak metamorphic condition at 9 kbar, 850°C. Assume a single layer crust of \(\rho = 3000 \, \text{kg/m}^3\) and \(g = 10 \, \text{m/sec}^2\) during metamorphism. The depth of burial during peak metamorphism is (give answer in kilometers).

Consider four minerals P, Q, R, and S in a three-component chemical system (A-B-C) as shown in the figure. For a crossing tie-line relationship, the variance (degrees of freedom) of the equilibrium mineral assemblage at X is
\includegraphics[width=0.5\linewidth]{57.jpeg}

The refractive indices of four minerals (P, Q, R, S) are as follows:
P (\(\alpha = 1.712, \beta = 1.721, \gamma = 1.727\)),
Q (\(\varepsilon = 1.553, \omega = 1.544\)),
R (\(\alpha = 1.664, \beta = 1.672, \gamma = 1.694\)) and
S (\(\omega = 1.658, \varepsilon = 1.486\))
The value of maximum birefringence among all the minerals is (give answer in three decimal places).

The mole% of forsterite component in olivine with chemical formula Mg₁₋ₓFeₓSiO₄ is

The Weiss symbol of a crystal face is 4a: 2b: c. The value of h in the corresponding Miller Index (hkl) is

In a mineral with chemical formula ATₓOₙ, the ionic radii of A and O are 1.12 Å and 1.40 Å, respectively. The co-ordination number of cation A is

Aluminium (Al) can occur in both tetrahedral and octahedral co-ordinations in silicates. The amount of octahedral Al in a pyroxene crystal of composition Mg₁.₄Fe₀.₄Al₀.₈Si₂O₆ is (give answer in one decimal place).

The birefringence of a mineral of thickness 30 μm and retardation 0.27 μm is (give answer in three decimal places).

Two limbs of a vertical chevron fold strike S70°E and N55°E. The value of the interlimb angle of the fold is (degree).

The core-rim compositions of a normally zoned plagioclase crystal are as follows:
Core: Ca₀.₆Na₀.₄Al₁.₆Si₂.₄O₈
Rim: Ca₀.₄Na₀.₆Al₁.₄Si₂.₆O₈
The amount of increase of Na atom from core to rim per formula unit of plagioclase is (give answer in one decimal place).

In an outcrop we find that the bedding planes are vertical and cleavage surfaces are horizontal. Which of the following fold types is/are inferred from this observation?

Which of the following stratigraphic unit(s) is/are coal/lignite bearing?

The Toposheet No(s). immediately adjacent to Toposheet No. 55J/8 is/are

Which of the following is/are NOT true for texturally immature sandstone?

P and S waves originate at earthquake focus and travel through the earth. Which of the following statements for these waves is/are correct?

An object is spotted at 60°E front bearing from the observer. If the position is interchanged, the front bearing value in degree from North (measured clockwise) is

Pressure (1GPa = 10 kbar) and temperature at the centre of the Earth are estimated to be

Choose the landform(s) resulting from glacial erosion.