List of top Geology and Geophysics Questions asked in GATE GG

A scalar potential \( \psi \) of a vector field \( \vec{F} \) satisfies the Laplace equation \( \nabla^2 \psi = 0 \) in free space. \( \psi \) can be uniquely determined at any point inside the closed surface \( S \) using:

Consider the acceleration due to gravity \( g' \) at an altitude \( h \) of 50 km above the Earth's surface. If \( R \) is the radius of the Earth, and the acceleration due to gravity measured at the surface is \( g \), the ratio of \( \frac{g'}{g} \) is ________. (Assume \( h \ll R \), \( R = 6370 \, {km} \), and round off to two decimal places.)

Consider a geophysical inverse problem of the form \( \mathbf{d} = \mathbf{G} \mathbf{m} \), where \( \mathbf{G} \) is the forward operator, \( \mathbf{m} \) is the model vector and \( \mathbf{d} \) is the observed data vector. The Earth model parameters can be estimated using \( \mathbf{m}_{{est}} = \mathbf{H} \mathbf{d} \), where \( \mathbf{H} \) is the pseudoinverse of \( \mathbf{G} \). Given \( \mathbf{G} = \mathbf{U} \Sigma \mathbf{V}^T \) as the singular value decomposition of \( \mathbf{G} \), and assuming \( \mathbf{G} \) is full rank, which of the following options is/are correct?

When an external magnetic field of strength \(1.5 \times 10^{-3}\) A/m is applied to a rock sample, the measured intensity of magnetization is \(0.5 \times 10^{-3}\) A/m. The magnetic susceptibility of this rock is ________ (Round off to two decimal places).

Half-life of \(^{14}C\) is 5730 years. Suppose we start with 1 billion \(^{14}C\) atoms, and after a certain interval of time only 125 million \(^{14}C\) atoms remain, the number of half-lives that has elapsed is ________ (Answer in integer).

F denotes force, A denotes area, L denotes length, and \( \Delta L \) is the change in length due to the applied force. Assuming linear elasticity, select a relationship where the constant of proportionality is a material property independent of the dimensions of the body.

The working of the proton-precession magnetometer is based on:

The following table provides the mineral chemistry of a garnet. All oxides are in weight percentage and cations in atoms per formula unit. Total oxygen is taken as 12 based on the ideal garnet formula. Consider Fe as Fetotal and Fe\(^{3+}\) = 0. The Xpyrope of this garnet is _.

230Th and 226Ra are intermediate nuclides in the decay series of 238U to 206Pb. The half-lives of 238U, 230Th, and 226Ra are 4.47 billion years, 75,000 years, and 1600 years, respectively. At secular equilibrium, when activities are equal, 10 billion atoms of 238U are present. The number of atoms of 226Ra present at equilibrium is ________

A sediment core of 4 cm diameter and 35.81 cm height was collected. This core had an initial weight of 1000.00 g and upon drying the sediment, the weight decreased by 133.75 g. This core has a void ratio of 0.42857, where void ratio is defined as the ratio of volume of void to the volume of solid (Vv/Vs). The average density of the sediment in the core is ________ g/cm\(^3\).

Which of the following options can be linked to rise in CO\(_2\) concentration in the atmosphere?

Which of the following statements is/are correct for electromagnetic (EM) radiation?

Choose the correct option(s) that describe(s) the properties of clay minerals.

Which of the following options is/are correct for movement of warm-base glaciers?

Choose the correct option(s) related to tectonic settings and associated rock types.

Choose the correct combination of minerals (listed in Group A) with the corresponding locations of their deposits (listed in Group B).