Folding occurs when compressional forces are applied to rocks, that are ductile or flexible.
The different types of folds are:
Symmetrical folds:
1. The axial plane is vertical.
2. The limbs are inclined at the same angle.
Asymmetrical folds:
1. The axial plane is inclined.
2. The limbs are inclined at different angles.
Overturned fold:
1. One limb lies above the other limb.
2. Limbs slope unequally in the same direction.
Recumbent fold:
1. Axial plane is almost horizontal.
2. One limb lies over the other in horizontal direction.
Isoclinal fold:
1. The limbs slope in the same direction with same amount.
2. The axial plane may be vertical, inclined or horizontal.
3. Slope of some portion of limbs is near vertical.
