Step 1: Understanding the concept.
Isostasy refers to the equilibrium that exists between the Earth's lithosphere and asthenosphere. It involves the vertical movement of the crust in response to changes in load. In continental mountain belts, this process leads to compensation, where the lithosphere adjusts to balance the weight of the mountains.
Step 2: Analyzing the options.
(A) compensation in: This is the correct answer, as isostatic compensation occurs in continental mountain belts.
(B) creation of: This is incorrect because isostasy does not create mountain belts; it adjusts the Earth's crust.
(C) destruction of: This is incorrect, as isostasy does not destroy mountain belts but helps maintain balance.
(D) thrusting in: Thrusting is a tectonic process, not directly related to isostatic compensation.
Step 3: Conclusion.
The correct answer is (A) compensation in because isostasy involves the adjustment of the Earth's crust in response to mountain formation.
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) 
Suppose a mountain at location A is in isostatic equilibrium with a column at location B, which is at sea-level, as shown in the figure. The height of the mountain is 4 km and the thickness of the crust at B is 1 km. Given that the densities of crust and mantle are 2700 kg/m\(^3\) and 3300 kg/m\(^3\), respectively, the thickness of the mountain root (r1) is km. (Answer in integer)


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) 
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) 
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 |
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)
The isobaric temperature-composition (T–X) phase diagram given below shows the phase relation between components M and N. The equilibrium melting undergone by the rock R to generate the liquid of composition L is .............. % (In integer )