Faults Flashcards
(19 cards)
Types of Normal Faults
Normal blind fault
Growth fault
Listric fault
Tilted fault blocks (array)
Array of faults
Faults that interact
Strain by faults stress feeds into faults they interact & feel each other
Thrusts (Overskydninger)
Load dipping reverse faults
Normal blind fault
Displacement decreases toward the tipline of the fault
The fault never reaches the topographic surface so it’s “blind”
Conjugate fault
Faults that form a complex pattern in two directions
Listric fault
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
Antithetic faults
Secondary fault, dipping
in opposite direction but generated
through the same event
Types of faults
- Normal
- Strike-slip
- Reverse
What words is used to describe a normal fault and its position?
-Hanging wall
-Footwall
-Throw (vertical)
-Heave (horizontal)
-Dip separation (displacement due to throw and heave)
Horst
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
Half-graben
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
Pitch
Direction of movement in a fault
(Not in dip direction)
What can you use to tell the direction of movement?
-Slickensides
-Dragfolds
-Offset linear features
-Cataclasites
Drag folds
Folding that takes place in the damage zone of the fault. Will be perpendicular to the axis of the movement
Heave
The offset along a fault plane, this can vary due to orientation
Slickensides
Orientation of minerals along the surface
Thrust
Load dipping reverse faults
Important in sedimentary succesions where there are weak surfaces (Salt clay, easily deformed)
What words can describe faults interacting with one another
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
Strike and slip faults
-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
