Question

Which of the following is not a correct statement?

• A. shear zones provide information about deformation
• B. shear zones help us to determine amount of strain
• C. shear zones help us to determine the cleavage
• D. shear zones help us to determine amount of displacement

Hint:

Cleavage is a fabric feature, not a strain measure. Shear zones help assess strain/displacement, not cleavage planes.

Answer 1

The Correct Option is C

To identify the incorrect statement about shear zones, let's analyze each option:

1. Understanding Shear Zones:
Shear zones are regions of concentrated deformation where rocks deform ductilely. They provide valuable information about:

• Deformation mechanisms (Option 1: Correct).
• Strain magnitude (Option 2: Correct).
• Displacement amounts (Option 4: Correct).

2. Key Issue with Option 3:
While shear zones may exhibit foliation or cleavage, cleavage is primarily determined by lithology and stress orientation, not directly by shear zones. Cleavage forms under specific stress conditions and is not a diagnostic feature of shear zones.

3. Why Other Options Are Correct:
- Shear zones record deformation history (Option 1).
- Strain markers (e.g., stretched clasts) quantify strain (Option 2).
- Offset markers (e.g., dykes) measure displacement (Option 4).

Final Answer:
The incorrect statement is: "shear zones help us to determine the cleavage".