Geology and Geophysics
GATE GG-1 year:2026 PYQs
Build your understanding with focused practice from past exam papers.
Questions 61–65 of 65. Imported answers require independent review unless marked reviewed.
Question 61
Open questionGGNAT2 marksNeeds review
An oblique-slip normal fault dipping 60°E shows a net slip of 100 m. If the net slip vector has a pitch of 30°, then the heave of the fault is ________ m (answer in integer).
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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).
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 63
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The Fe-Mg exchange reaction between olivine and spinel is the following:
Mg₂SiO₄ + 2FeAl₂O₄ ↔ Fe₂SiO₄ + 2MgAl₂O₄
(Fosterite) (Fe-spinel) (Fayalite) (Mg-spinel)
Assuming ideal solid solutions, the temperature of equilibrium between olivine and spinel using the following data is __________ °C (round off to nearest integer).
[Assume that ΔHᵣ⁰ and ΔSᵣ⁰ are independent of P and T, and Kd is independent of P]
| ΔHᵣ⁰ (kJ/mol) | ΔSᵣ⁰ (J/mol. K) | Kd = [(xFe^Ol xMg^Sp)/(xMg^Ol xFe^Sp)]² | R (J/mol. K) |
| −10.91 | −3.90 | 3.024 | 8.314 |
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The bore hole distribution of a massive sulphide deposit represented in the form of 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]
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An aquifer has a surface area of 100 km². With no recharge, assume that pumping out 2 × 10⁷ 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).
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