Faults

Question 1

Types of Normal Faults

Answer 1

Normal blind fault
Growth fault
Listric fault
Tilted fault blocks (array)

Question 2

Array of faults

Answer 2

Faults that interact

Strain by faults stress feeds into faults they interact & feel each other

Question 3

Thrusts (Overskydninger)

Answer 3

Load dipping reverse faults

Question 4

Normal blind fault

Answer 4

Displacement decreases toward the tipline of the fault
The fault never reaches the topographic surface so it’s “blind”

Question 5

Conjugate fault

Answer 5

Faults that form a complex pattern in two directions

Question 6

Listric fault

Answer 6

A fault with a curved plane due to a surface with no strength (fx. plastic clay)

The rollover in a listric fault can form a wedge, and a new fault can occur creating a series of many faults

Question 7

Antithetic faults

Answer 7

Secondary fault, dipping
in opposite direction but generated
through the same event

Question 8

Types of faults

Answer 8

• Normal
• Strike-slip
• Reverse

Question 9

What words is used to describe a normal fault and its position?

Answer 9

-Hanging wall
-Footwall
-Throw (vertical)
-Heave (horizontal)
-Dip separation (displacement due to throw and heave)

Question 10

Horst

Answer 10

A normal fault where the footwall sits above a hanging wall on both sides. This does not mean compression. The foot walls could have fallen down

Question 11

Half-graben

Answer 11

A normal fault where there is rollover reverse drag, far away from the rollover the hanging wall and footwall ends up being at the same level

Question 12

Pitch

Answer 12

Direction of movement in a fault
(Not in dip direction)

Question 13

What can you use to tell the direction of movement?

Answer 13

-Slickensides
-Dragfolds
-Offset linear features
-Cataclasites

Question 14

Drag folds

Answer 14

Folding that takes place in the damage zone of the fault. Will be perpendicular to the axis of the movement

Question 15

Heave

Answer 15

The offset along a fault plane, this can vary due to orientation

Question 16

Slickensides

Answer 16

Orientation of minerals along the surface

Question 17

Thrust

Answer 17

Load dipping reverse faults

Important in sedimentary succesions where there are weak surfaces (Salt clay, easily deformed)

Question 18

What words can describe faults interacting with one another

Answer 18

Soft link: No surface running from one fault to another but can feel one another

Hard-linked segment: The faults are now combined and will only move in one fault

Faults can be hard-linked in one area and soft-linked in another if you go further down in one fault

Question 19

Strike and slip faults

Answer 19

-Lateral movement
-Can form a pull-apart basin.
-Folds initiate at 45 deg.
- Plates moving toward one another = positive flowerstructure
-Pull apart basin = Negative flower structure