Flashcards on Geological Fold Geometry and Characteristics

Geological Fold Geometry and Characteristics Explained

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What is the plunge of a fold axis measured as?

The angle between the fold axis and the horizontal, measured in a Vapho plane (angle of plunge).

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Fold Geometry (Structural Geology)

6 cards

Card 1

Question: What is the plunge of a fold axis measured as?

Answer: The angle between the fold axis and the horizontal, measured in a Vapho plane (angle of plunge).

Card 2

Question: How is a complete description of plunge expressed?

Answer: By the amount (angle) of plunge and the direction of plunge (bearing).

Card 3

Question: Give an example of describing a fold's plunge.

Answer: A fold may be described as having a plunge of 30° towards (on a bearing of) 105°.

Card 4

Question: What is the amplitude of a fold (height) and how is it measured?

Answer: The amplitude (height) is measured by taking half the distance from the hinge to the line joining the two hinges on each side of the fold.

Card 5

Question: What is the wavelength of a fold and how is it measured?

Answer: The wavelength is the distance measured between hinges on each side of the fold.

Card 6

Question: What is an inflexion point in fold geometry?

Answer: An inflexion point is where the sense of curvature changes from one fold to the next.