Chevron (geology)

Chevron folds with flat-lying axial planes, Millook Haven, North Cornwall

Chevron crevasses on a glacier

A chevron in geology is a sharply-folded rock formation. Chevron folds are regular folded beds with straight limbs and sharp hinges. Well developed, these folds produce a set of v-shaped beds.^[1]

They develop in response to compressive stress. The angles of the folds are generally 60 degrees or less. Chevron folding is helped if the bedding alternates between beds of different make-up.^[1] Turbidites,^[2] with alternating sandstones and shales, are the typical geological setting for chevron folds to occurs.^[3]

Chevrons can also form in land deposits, especially where there are sand dunes.

References

1. Ramsay, J (1974). "Development of chevron folds". Geological Society of America Bulletin. 85 (11): 1741. doi:10.1130/0016-7606(1974)85<1741:docf>2.0.co;2.
2. Deposits in the deep ocean from gravity flow of sediments.
3. Reches, Z E; Johnson (1976). "A theory of concentric, kink and sinusoidal folding and of monoclinal flexuring of compressible, elastic multilayers: VI. Asymmetric folding and monoclinal kinking". Tectonophysics. 35 (4): 295–334. doi:10.1016/0040-1951(76)90074-3.