In clastic sediments, the correct order of decreasing grain size is
Show Hint
- Boulder > pebble > silt > sand
- Granule > pebble > clay > silt
- Cobble > granule > silt > clay
- Granule > pebble > sand > silt
The Correct Option is C
Solution and Explanation
Step 1: Evaluating each option:
(A) Boulder > pebble > silt > sand: Incorrect order: sand is coarser than silt
(B) Granule > pebble > clay > silt: Incorrect: pebble is larger than granule. Silt is coarser than clay
(C) Cobble > granule > silt > clay: Cobble (64-256 mm) > Granule (2-4 mm) > Silt (0.0039-0.0625 mm) > Clay (<0.0039 mm). This is the correct decreasing order
(D) Granule > pebble > sand > silt: Incorrect: pebble is larger than granule
Answer: (C) Cobble > granule > silt > clay
Top IIT JAM GG Geology Questions
A magma having density of 2900 kg m\(^-3\) just reaches the surface through a two-layered crust as shown in the figure below. Assuming isostatic equilibrium, its depth of melting is .......... km. (Round off to one decimal place)
- IIT JAM GG - 2025
- Geology
- Geophysics
Two boreholes A and B, both inclined towards 270°, penetrate a dipping coal bed at the same point and pass through it entirely in the sub-surface as shown in the figure below. The bed dips towards 270°. The thickness of the coal bed, measured along the borehole A is 10 m and along borehole B is 8 m. The angle between the two boreholes is 20°. The orthogonal thickness \( x \) of the coal bed is ........ m. (Round off to one decimal place)
- IIT JAM GG - 2025
- Geology
- Applied Geology
A well-developed succession of laminated shale is bound by two volcanic ash beds that were precisely dated as shown in the schematic diagram given below. Assuming a constant sedimentation rate, the age of the fossiliferous limestone bed 65 m above the basal volcanic ash bed is ............ Ma. (Round off to nearest integer)
- IIT JAM GG - 2025
- Geology
- Stratigraphy
The data tabulated below are for flooding events in the last 400 years.
The probability of a large flood accompanied by a glacial lake outburst flood (GLOF) in 2025 is ........... \(\times 10^{-3}\). (Round off to one decimal place)
Year Flood Size Magnitude rank 1625 Large 2 1658 Large + GLOF 1 1692 Small 4 1704 Large 2 1767 Large 2 1806 Small 4 1872 Large + GLOF 1 1909 Large 2 1932 Large 2 1966 Medium 3 2023 Large + GLOF 1 - IIT JAM GG - 2025
- Geology
- Applied Geology
A satellite launching vehicle is carrying a lander for Moon mapping.
As shown in the figure below, P is the position where the gravitational forces exerted by Earth and Moon on the vehicle balance out.
The distance \( P \) from the center of the Earth is ........... \(\times 10^5\) km. (Round off to two decimal places)
- IIT JAM GG - 2025
- Geology
- Applied Geology
Top IIT JAM GG Sedimentology Questions
- A marine organic-rich, black shale with tiny pyrite crystals shows complete absence of body or trace fossils. Which of the following statement(s) is/are TRUE?
- IIT JAM GG - 2021
- Geology
- Sedimentology
- Following are the statements regarding types of sandstone as per Pettijohn’s classification. Which is/are the CORRECT statement(s) out of the following?
- IIT JAM GG - 2021
- Geology
- Sedimentology
Match the primary sedimentary structure in Group I with the corresponding process of formation in Group II.
\[\begin{array}{|l|l|} \hline \textbf{Group I} & \textbf{Group II} \\ \hline \text{P. Asymmetric ripples} & \text{1. Water escape} \\ \hline \text{Q. Dish and pillar} & \text{2. Bed load transportation of sediments} \\ \hline \text{R. Flute cast} & \text{3. Deposition from alternate traction and suspension load} \\ \hline \text{S. Wavy bedding} & \text{4. Scouring by turbulent eddy} \\ \hline \end{array}\]- IIT JAM GG - 2020
- Geology
- Sedimentology
- Find out the correct statement(s).
- IIT JAM GG - 2020
- Geology
- Sedimentology
From the data shown in the table, the weighted mean size (in micrometer, correct to two decimal places) of the sediment population is ............
\[ \begin{array}{|c|c|} \hline \text{Grain Size (micrometer)} & \text{Dry Sediment Weight (in gram)} \\ \hline 4 & 50 \\ 20 & 75 \\ 40 & 125 \\ 60 & 50 \\ \hline \end{array} \]- IIT JAM GG - 2020
- Geology
- Sedimentology
Top IIT JAM GG Questions
A magma having density of 2900 kg m\(^-3\) just reaches the surface through a two-layered crust as shown in the figure below. Assuming isostatic equilibrium, its depth of melting is .......... km. (Round off to one decimal place)
- IIT JAM GG - 2025
- Geophysics
Two boreholes A and B, both inclined towards 270°, penetrate a dipping coal bed at the same point and pass through it entirely in the sub-surface as shown in the figure below. The bed dips towards 270°. The thickness of the coal bed, measured along the borehole A is 10 m and along borehole B is 8 m. The angle between the two boreholes is 20°. The orthogonal thickness \( x \) of the coal bed is ........ m. (Round off to one decimal place)
- IIT JAM GG - 2025
- Applied Geology
A well-developed succession of laminated shale is bound by two volcanic ash beds that were precisely dated as shown in the schematic diagram given below. Assuming a constant sedimentation rate, the age of the fossiliferous limestone bed 65 m above the basal volcanic ash bed is ............ Ma. (Round off to nearest integer)
- IIT JAM GG - 2025
- Stratigraphy
The data tabulated below are for flooding events in the last 400 years.
The probability of a large flood accompanied by a glacial lake outburst flood (GLOF) in 2025 is ........... \(\times 10^{-3}\). (Round off to one decimal place)
Year Flood Size Magnitude rank 1625 Large 2 1658 Large + GLOF 1 1692 Small 4 1704 Large 2 1767 Large 2 1806 Small 4 1872 Large + GLOF 1 1909 Large 2 1932 Large 2 1966 Medium 3 2023 Large + GLOF 1 - IIT JAM GG - 2025
- Applied Geology
A satellite launching vehicle is carrying a lander for Moon mapping.
As shown in the figure below, P is the position where the gravitational forces exerted by Earth and Moon on the vehicle balance out.
The distance \( P \) from the center of the Earth is ........... \(\times 10^5\) km. (Round off to two decimal places)- IIT JAM GG - 2025
- Applied Geology