Question:
The attitude of the two limbs of a fold was measured as striking 4° N, dipping 85° easterly and striking 30° N, dipping 60° easterly. Which of the following is/are TRUE for describing the geometry of the fold?
The attitude of the two limbs of a fold was measured as striking 4° N, dipping 85° easterly and striking 30° N, dipping 60° easterly. Which of the following is/are TRUE for describing the geometry of the fold?
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If both limbs dip toward each other → Antiform/Synform (depending on closure).
If both dip in the same direction → Overturned or inclined fold.
Updated On: Dec 6, 2025
- Synform
- Antiform
- Overturned
- Plunging
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The Correct Option is A, B, C, D
Solution and Explanation
Step 1: Interpreting limb orientations.
Both limbs dip in the same general direction (easterly) but at different angles (85° and 60°). When both limbs dip toward the same side, the fold must be overturned or inclined in that direction. The fold axis trends approximately between the strikes.
Step 2: Fold shape.
Since both limbs dip eastward, the fold closes downward, forming a synform.
Step 3: Determining other properties.
There is no indication of the axial plane being overturned (beyond both dips in one direction), so it is best classified as a synform.
Step 4: Conclusion.
Thus, the correct description of the fold is (A) Synform.
Both limbs dip in the same general direction (easterly) but at different angles (85° and 60°). When both limbs dip toward the same side, the fold must be overturned or inclined in that direction. The fold axis trends approximately between the strikes.
Step 2: Fold shape.
Since both limbs dip eastward, the fold closes downward, forming a synform.
Step 3: Determining other properties.
There is no indication of the axial plane being overturned (beyond both dips in one direction), so it is best classified as a synform.
Step 4: Conclusion.
Thus, the correct description of the fold is (A) Synform.
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