A chevron in geology is a distinctive style of folded strata in which beds form straight limbs separated by acute, angular hinges. Such structures are often referred to as chevron folds and are recognizable in outcrop by their regular V-shaped geometry. When well developed they produce a repeating pattern of sharp, pointed folds rather than the smooth, rounded forms typical of many other folding styles.

Diagnostic characteristics

Chevron folds have a characteristic set of features that help distinguish them from other fold types. Typical traits include:

  • Nearly planar or straight limbs connected by narrow hinge zones.
  • Interlimb angles that are commonly 60 degrees or less, producing acute "V" shapes; see discussions of fold angles at related resources.
  • Regular spacing and repetition when a multilayered sequence reacts coherently to stress.
  • Association with sequences that alternate between mechanically strong and weak layers.

How chevrons form

Chevron folding develops under crustal shortening driven by compressive forces. Buckling of layered rocks is promoted where competent, stiff beds are interbedded with thin, more ductile layers; mechanisms such as layer-parallel shortening and flexural slip accommodate the deformation. Regional compressive stress during mountain building or basin inversion can produce chevrons on scales from decimetres to many metres.

One of the classic settings for chevron folds is in turbidite sequences, where alternating sandstone and shale beds have contrasting strength. The competence contrast encourages straight limbs in the strong beds while the weak beds deform more readily at hinges.

Chevrons are useful structural indicators: their geometry can reveal the direction and intensity of shortening, influence fluid flow and reservoir distribution in sedimentary basins, and affect slope stability in engineering projects. In a different context, the term "chevron" is also applied to V-shaped dune and coastal deposits; interpretations of those landforms (storm versus tsunami origin) are debated and require careful sedimentary analysis.