When rocks deform in a ductile manner, instead of fracturing to form faults or joints, they may bend or fold, and the resulting structures are called folds. Folds result from
compressional stresses or shear stresses
acting over considerable time.
What type of stress is placed on folds quizlet?
squeezes rock together causing rocks to fold or fracture(break)
Compression
is the most common stress at convergent boundaries. Rocks that are pulled apart are under tension; rocks under tension lengthen or break apart.
What type of stress is placed on a strike slip fault?
A strike-slip fault is a nearly vertical dip-slip fault in which fault blocks move horizontally, parallel to the fault strike. In this kind of fault, both the
maximum and minimum principal stresses are horizontal
while the intermediate stress is vertical.
What type of stress can create 2 kinds of folds?
Tension
is stress that occurs when forces act to stretch an object. folding. B. B. Types of Folds The two most common types of folds— anticlines, or upward-arching folds, and synclines, down-ward, trough-like folds. Another type of fold is a monocline.
Which conditions can cause folding?
Folds form under varied conditions of
stress, pore pressure, and temperature gradient
, as evidenced by their presence in soft sediments, the full spectrum of metamorphic rocks, and even as primary flow structures in some igneous rocks.
What are the 3 fault types?
There are three main types of fault which can cause earthquakes:
normal, reverse (thrust) and strike-slip
. Figure 1 shows the types of faults that can cause earthquakes. Figures 2 and 3 show the location of large earthquakes over the past few decades.
Are faults convergent or divergent?
Reverse faults occur at convergent plate boundaries, while
normal faults occur at divergent plate boundaries
. Earthquakes along strike-slip faults at transform plate boundaries generally do not cause tsunami because there is little or no vertical movement.
What type of stress is put on a normal fault?
Tensional stress
, meaning rocks pulling apart from each other, creates a normal fault. With normal faults, the hanging wall and footwall are pulled apart from each other, and the hanging wall drops down relative to the footwall.
What are the 4 types of faults?
There are four types of faulting
— normal, reverse, strike-slip, and oblique
. A normal fault is one in which the rocks above the fault plane, or hanging wall, move down relative to the rocks below the fault plane, or footwall. A reverse fault is one in which the hanging wall moves up relative to the footwall.
What is shear stress in earth science?
Shear stress is
the stress component parallel to a given surface
, such as a fault plane, that results from forces applied parallel to the surface or from remote forces transmitted through the surrounding rock.
What force causes folding?
10.6a:
Compressive forces
generate folding and faulting as a consequence of shortening. Compressive forces are common along convergent plate boundaries resulting in mountain ranges.
Which type of stress is a uniform?
This uniform stress is called
lithostatic pressure
and it comes from the weight of rock above a given point in the earth. Lithostatic pressure is also called hydrostatic pressure.
How are Ptygmatic folds formed?
boudinage structures develop when
the veins are so oriented
that a component of extensive strain is parallel to the veins. … Ptygmatic folding and pinching-and-swelling or boudinage are consequently complimentary phenomena which can develop simultaneously in response to the same stress system in the host rock.
What direction is the fold plunging?
A plunging fold is a fold that is tilted
downwards in space
, parallel to the fold hinge plane.
How many types of folds are there with plunge as a basis?
1. How many types of folds are there with plunge as a basis? Explanation: Only
two main types
are recognized as the types of folds on the basis plunge.
Which is an example of reverse fault?
A reverse fault is called a thrust fault if the dip of the fault plane is small. Other names: thrust fault, reverse-slip fault or compressional fault. Examples:
Rocky Mountains, Himalayas
.
