Flashcards in FOLDS AND FAULTS Deck (22)
What is the difference between stress and strain?
-Stress is the force applied over an area
-strain is the change or distortion produced by a stress
Stress that acts equaly from all directions is-
if it is not equal it is-
-results in slippage and destortion
What is elastic deformation?
when the rock returns to it's original shape when the stress is removed
What is the yield point or elastic limit?
The maximum stress a given rock can withstand without becoming permanently deformed. showing plastic or ductile behavior
Describe a brittle maerial
have a small or large region of elastic
behaviour but only a small region of ductile behaviour before they fracture.
describe a ductile material
have a small region of elastic
behaviour and a large region of ductile behaviour before they fracture.
Name 5 factors that effect the brittle/ductile nature of the rock
-presence of water
wich minerals are 1) brittle and 2) ductile?
1) quartz, olivene, f'spar
2)caly, mica, calcite
define 1)competent and 2) incompetent rocks
rocks that only deform under 1) great stress 2) moderate to low stress
describe a dip slip fault
Dip slip faults are faults that have an inclined fault plane and
along which the relative displacement or offset has occurred
along the dip direction.
describe a strike slip fault
Here the fault surface is usually near vertical and the footwall
moves either left or right or laterally with very small vertical
what is a thrust fault?
low angle reverse fault
what is a slickenside?
parralel sirations on rock face produced by relative motion alog fault planes
what is fault gouge?
debri produced by the crushing and grinding of rough rock surfaces on each side of a fault
what is fault breccia?
Fragmented rock in which angular fragments were formed by brittle fault movement; fault breccia occurs along a fault.
what is mylonite?
a cleavegeless rock with a strecky banded structure.
produced by the extreme
granulation and shearing of rocks that have
been pulverized and rolled during
overthrusting or intense dynamic
MICCROBRECCIA WITH FLOW TEXTURE
Where is the 1) hinge and 2) limb of a fold?
1) the place where the rocks are bent
2)the two sides
what is the axial plane? and what is 'axial plane trace'
the line that bisects the angle of the fold.
it's trace is where it intersects the earth's surface
what is the 1)wavelength and 2) amplitude of a fold
1) the distance between two crests/ troughs
2) half the vertical distance between the crecst and trough of a fold
What are 1) upfolds and 2) downfolds called?
1) antiforms 2) synforms