Flashcards on Geological Fold Types and Geometry
Geological Fold Types and Geometry: A Student's Guide
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Geological folds
10 cards
Card 1
Question: What determines the size of the interlink angle in a fold?
Answer: The angularity of the hinge zone (i.e., how sharply the limbs join at the hinge).
Card 2
Question: What term describes a fold with a small radius of curvature at the hinge zone relative to the length of the fold limb?
Answer: Angular fold (hinge zone has a small radius of curvature relative to limb length).
Card 3
Question: What term describes a fold with a large radius of curvature at the hinge zone relative to the length of the fold limb?
Answer: Rounded fold (hinge zone has a large radius of curvature relative to limb length).
Card 4
Question: What is meant by the 'fold profile'?
Answer: The fold profile is the shape of a folded layer observed in the plane perpendicular (I) to the fold axis; it is the cross-sectional view showing geome
Card 5
Question: In which plane is the fold profile observed?
Answer: In the plane perpendicular (I) to the fold axis (the cross-sectional view).
Card 6
Question: What does the fold profile show?
Answer: The geometry of the hinge, limbs, and axial plane of the folded layer.
Card 7
Question: What are 'parallel folds' with respect to adjacent fold surfaces?
Answer: Parallel folds are those in which the adjacent fold surfaces bounding the folded layer are parallel (thickness measured perpendicular to the fold surf
Card 8
Question: How is layer thickness measured in a parallel fold?
Answer: The thickness measured perpendicular (I) to the fold surface is constant.
Card 9
Question: What is a special case of parallel folds where adjacent fold surfaces are arcs of a circle?
Answer: Concentric fold.
Card 10
Question: In a concentric fold, what is common to the arcs that form adjacent fold surfaces?
Answer: They share a common center, known as the center of curvature of the fold.