Lecture 4 at a glance
Folds: Monocline, syncline, anticline
Measurable structural elements: Axial plane, fold axis, axial planar cleavage, crenulation, intersection lineation.
Asymmetrical
Overturned
Recumbent
You can easily get an apparently overturned fold (or even a recumbent fold) from a 2D section through a symmetric fold. So make sure that the shape of the fold is describe in the plane perpendicular to the fold axis: i.e the profile plane.
When folding occurs at depth>5km, a cleavage plane may develop. It tends to be parallel to the folds axial planar surface.
You can locate yourself on a fold by looking at the angular relationship between the bedding plane and the cleavage plane.
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