What is hinge line in geography?
What is hinge line in geography?
[′hinj ‚līn] (geology) The line separating the region in which a beach has been thrust upward from that in which it is horizontal. A line in the plane of a hinge fault separating the part of a fault along which thrust or reverse movement occurred from that having normal movement.
What is the hinge line of a fold?
Hinge line = where the limbs of the fold meet. It is also the line of maximum curvature. Axial Surface (or Axial Plane if it’s not curved) of a stack of folds passes through the hinge lines and most nearly divides the fold into two equal parts.
What is hinge point in geology?
The point of maximum curvature of a folded layer is located in the centre of the hinge zone and is called the hinge point. Hinge points are connected in three dimensions by a hinge line. The hinge line is commonly found to be curved, but where it appears as a straight line it is called the fold axis.
What are faults and folds?
Folds constitute the twists and bends in rocks. Faults are planes of detachment resulting when rocks on either side of the displacement slip past one another. The type of strain (deformation) that develops in a rock depends on the tectonic force.
What type of structure do Synclines form?
In a syncline the youngest beds, the ones that were originally on top of the rest of the beds, are at the center, along the axis of the fold. Anticlines and synclines form in sections of the crust that are undergoing compression, places where the crust is being pushed together.
What is plunge of fold?
Plunge is the vertical angle between the horizontal plane and the axis or line of maximum elongation of a feature. Plunge is measured along the axis of a fold, whereas dip is measured along the limbs.
Which fold has two hinges?
Conjugate folds
Explanation: Conjugate folds are composite folds characterised with two hinges and three planar limbs in which the central limb is exceptionally flattened.
What are the 4 types of folds?
Types of Folds
- Anticline: linear, strata normally dip away from axial center, oldest strata in center.
- Syncline: linear, strata normally dip toward axial center, youngest strata in center.
- Antiform: linear, strata dip away from axial center, age unknown, or inverted.
How do you identify a fold in field?
Recognition of folds in the field: 1) The easiest and simplest way is the eye inspection. If we found any geological structure according to the normal definition of a fold then it can be identified as fold only by direct observation. 2) The repetition and absence of beds also indicates the presence of fold.
What is a hinge line in geology?
Hinge Line. a line connecting the points of maximum bending of the strata in a fold. fold, each stratum has its own hinge line, and the plane that passes through the corresponding series of hinge lines is called the axial surface of the fold.
What are the hinge lines of a fold?
Hinge lines: (a) the hinge line of an anticline, (b) the hinge line of a syncline fold, each stratum has its own hinge line, and the plane that passes through the corresponding series of hinge lines is called the axial surface of the fold.
What are the different types of hinges?
A spectrum of hinge shapes exists, from the pointed hinges of kink bands and chevron folds (sharp and angular folds) to the well-rounded hinges of concentric folds. Classification of folds relative to hinge curvature is referred to as bluntness.
How do you plot bedding poles on a geological map?
Dip and strike data on each fold limb are plotted as poles to bedding. We can also locate on the geological map the hinge points for each layer. The line connecting hinge points must lie on the axial surface.
