What are kinks in geology?
Definitions and Terminology. Kink bands are structures common in the deformation of solids with a well-developed and mechanically effective planar foliation. Geologic interest in kink bands derives from their occurrence in foliated rock where bedding, cleavage, or schistosity acts as an effective glide plane.
How are kink bands formed?
Kinking occurs when slip on a single slip plane is inadequate to maintain homogeneous deformation. The grain sharply bends (kinks) and the deformation localizes into kink bands, which enable shortening of the grain to continue.
What are the 3 types of folds that can form in rocks?
Three forms of folds: syncline, anticline, and monocline.
What is kink band fold?
Kink-bands are tabular fold-zones resulting from the operation of a shear couple and commonly occur as conjugate sets, usually developing late in the structural history of orogenic systems. The geometry of kink-bands has been investigated in an attempt to determine possible mechanisms of deformation.
How do chevron folds form?
Chevron folds are a structural feature characterized by repeated well behaved folded beds with straight limbs and sharp hinges. Well developed, these folds develop repeated set of v-shaped beds. They develop in response to regional or local compressive stress. Inter-limb angles are generally 60 degrees or less.
How do you classify folds?
Folds are classified into two main types namely anticlines or up-folds and synclines or down-folds.
What is kink fold?
Kink folds form in rocks with regular layering, either in regular sedimentary bedding or as a late stage fold in foliation. Conjugate folds are paired folds with paired axial surfaces symmetrical to each other. Kink in Precambrian-Wallace Fm.
How are folds formed geology?
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.
What are the kinds of fabric folds?
How to Draw Clothing Folds: 6 Different Types
- Pipe Fold. Pipe folds tend to occur on dresses and curtains.
- Zig-Zag Fold. Zig-zag folds tend to occur where pants bunch up at the bottom of the legs or behind the knees.
- Spiral Fold.
- Half-Lock Fold.
- Diaper Fold.
- Drop Fold.
What is Isoclinal fold?
or isocline, a fold in sedimentary rocks where the axial surface and limbs slope in the same direction and at approximately the same angle. Isoclinal folds are formed under conditions of intensive lateral compression or with slipping brought about by the force of gravity.
What kind of rock has a kink fold?
Kink folds form in rocks with regular layering, either in regular sedimentary bedding or as a late stage fold in foliation. Conjugate foldsare paired folds with paired axial surfaces symmetrical to each other. 64_242.
What is the angle of a kink fold?
Kink folds theoretically can initiate only in layers inclined at angles less than * (45’ – Q/2) to the direction of maximum compression. Here Q is the angle of internal friction 01 contacts.
How is folding related to the rheology of rock?
Other terms are related to how the layer (s) react to force and stress, for instance whether layers fold by layer-parallel shearing, orthogonal flexure or some other mechanism that is controlled by rock rheology. Still other classes of folding, such as kinking and chevron folding, are related to fold geometry.
How are kinking and Chevron folding related to fold geometry?
Still other classes of folding, such as kinking and chevron folding, are related to fold geometry. For this reason, several different fold mechanisms are defined, and many of them overlap in definition.