Question:
Which of the following rocks occurs typically in a ductile shear zone?
Which of the following rocks occurs typically in a ductile shear zone?
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Mylonites are characteristic of ductile shear zones, formed under conditions of high strain and low to moderate temperatures.
Updated On: Dec 11, 2025
- Gouge
- Breccia
- Pseudotachylite
- Mylonite
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The Correct Option is D
Solution and Explanation
Step 1: Understanding Ductile Shear Zones.
Ductile shear zones are zones of deformation where rocks are subjected to high strain, leading to the formation of fine-grained, deformed rocks. These rocks typically exhibit a foliated texture.
Step 2: Analyzing the options.
(A) Gouge: Incorrect — Gouge is a fine-grained material formed by the grinding and breaking of rock along faults, but it is not typical of ductile shear zones.
(B) Breccia: Incorrect — Breccia consists of angular fragments and is associated with brittle deformation, not ductile shear zones.
(C) Pseudotachylite: Incorrect — Pseudotachylite forms in frictionally heated rocks during faulting, but it is not typical of ductile shear zones.
(D) Mylonite: Correct — Mylonite forms in ductile shear zones due to intense deformation and fine-grained texture.
Step 3: Conclusion.
The correct answer is (D) Mylonite, as it is the rock typically found in ductile shear zones.
Ductile shear zones are zones of deformation where rocks are subjected to high strain, leading to the formation of fine-grained, deformed rocks. These rocks typically exhibit a foliated texture.
Step 2: Analyzing the options.
(A) Gouge: Incorrect — Gouge is a fine-grained material formed by the grinding and breaking of rock along faults, but it is not typical of ductile shear zones.
(B) Breccia: Incorrect — Breccia consists of angular fragments and is associated with brittle deformation, not ductile shear zones.
(C) Pseudotachylite: Incorrect — Pseudotachylite forms in frictionally heated rocks during faulting, but it is not typical of ductile shear zones.
(D) Mylonite: Correct — Mylonite forms in ductile shear zones due to intense deformation and fine-grained texture.
Step 3: Conclusion.
The correct answer is (D) Mylonite, as it is the rock typically found in ductile shear zones.
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