In structural geology, a fold is a stack of originally planar surfaces, such as sedimentary strata, that are bent or curved ("folded") during permanent deformation. Folds in rocks vary in size from microscopic crinkles to mountain-sized folds.

fold, in geology, undulation or waves in the stratified rocks of Earth’s crust. Stratified rocks were originally formed from sediments that were deposited in flat horizontal sheets, but in a number of places the strata are no longer horizontal but have been warped.

Folds are some of the most striking and spectacular features of the Earth’s crust. In most cases, folds form where layered rocks have been shortened. Folds are very common, therefore, in orogenic belts – regions where the Earth’s lithosphere has undergone shortening as a result of plate movements. Orogenic belts often form mountain ranges.

In a series of folds it is evident like waves. They consist of alternate crests and troughs. The crest of the fold is termed as anticline while the trough is called synclines. An anticline and syncline constitute a fold. Limbs or a flank of the fold is sloping side from the crest to the trough.

2015年12月26日 · Folds are commonly formed by shortening of existing layers, but may also be formed as a result of displacement on a non-planar fault (fault bend fold), at the tip of a propagating fault (fault propagation fold), by differential compaction or due to the effects of a high-level igneous intrusion e.g. above a laccolith.

Geologic folds are layers of rock that are curved or bent by ductile deformation. Folds are most commonly formed by compressional forces at depth, where hotter temperatures and higher confining pressures allow ductile deformation to occur. Folds are described by the orientation of their axes, axial planes, and limbs.

2023年4月23日 · Folds are wavelike deformation patterns in rock layers or other geological materials that result from the application of stress over a period of time. This process causes the originally flat or layered rocks to bend and deform, creating …

Folds are classified on the basis of several geometric factors: Tightness of folding. The tighness of folds can be described as open (limbs dip gently), tight (limbs dip steeply) or isoclinal (limbs are parallel).

A fold is a geologic structure that is formed by layers or beds of rock being bent or folded. The plane that marks the center of the fold is called the axial plane. The line which marks where the axial plane intersects the surface of Earth is called the hinge line.

Geological folds are the curvatures in rocks or strata containing them. Most visible stratified rocks are located in the rivers, quarries or coasts were, originally, sediment layers deposited in horizontal or near horizontal beds.