Flashcards on Classification of Geological Folds

Classification of Geological Folds: A Student's Guide

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What four main features are used to classify geological folds?

Direction of closing; Attitude of the axial trace; Size of the interlimb angle; Feature of profile.

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Geological folds (fold classification)

7 cards

Card 1

Question: What four main features are used to classify geological folds?

Answer: Direction of closing; Attitude of the axial trace; Size of the interlimb angle; Feature of profile.

Card 2

Question: What does 'direction of closing' refer to in fold classification?

Answer: Whether a fold closes upwards, downwards, or sideways (facing/closing direction).

Card 3

Question: What is an antiform (anticline) in terms of limb dip and rock age in the core?

Answer: A fold that closes upwards where limbs dip away from the hinge; bedding becomes younger upwards; it contains older rocks in its core (anticline).

Card 4

Question: How is a synform (syncline) defined regarding limb dip and rock age in the core?

Answer: A fold that closes downwards where limbs dip towards the hinge; a syncline/synform contains younger rocks in its core.

Card 5

Question: What term is used for folds that close sideways?

Answer: Neutral folds (folds which close sideways).

Card 6

Question: What is the difference between the terms 'antiform' and 'anticline' as used here?

Answer: Antiform describes the shape (limbs dip away from hinge); anticline is the more familiar name when it contains older rocks in its core (bedding younge

Card 7

Question: What is the relationship between 'synform' and 'syncline' as used in the classification?

Answer: Synform describes the downward-closing shape (limbs dip toward hinge); syncline is the term used when it contains younger rocks in its core.