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Flashcards in FOLDS AND FAULTS Deck (22)
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1

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

2

Stress that acts equaly from all directions is-
if it is not equal it is-

Uniform
Diferential

3

Tensional stress-
Compressional stress-
shear stress-

-streches rock
-compresses rock
-results in slippage and destortion

4

What is elastic deformation?

when the rock returns to it's original shape when the stress is removed

5

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

6

Describe a brittle maerial

have a small or large region of elastic
behaviour but only a small region of ductile behaviour before they fracture.

7

describe a ductile material

have a small region of elastic
behaviour and a large region of ductile behaviour before they fracture.

8

Name 5 factors that effect the brittle/ductile nature of the rock

-time
-tempreture
-confining pressure
-composition
-presence of water

9

wich minerals are 1) brittle and 2) ductile?

1) quartz, olivene, f'spar
2)caly, mica, calcite

10

define 1)competent and 2) incompetent rocks

rocks that only deform under 1) great stress 2) moderate to low stress

11

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.

12

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
motion.

13

what is a thrust fault?

low angle reverse fault

14

what is a slickenside?

parralel sirations on rock face produced by relative motion alog fault planes

15

what is fault gouge?

debri produced by the crushing and grinding of rough rock surfaces on each side of a fault

16

what is fault breccia?

Fragmented rock in which angular fragments were formed by brittle fault movement; fault breccia occurs along a fault.

17

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
metamorphism.
MICCROBRECCIA WITH FLOW TEXTURE

18

Where is the 1) hinge and 2) limb of a fold?

1) the place where the rocks are bent
2)the two sides

19

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

20

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

21

What are 1) upfolds and 2) downfolds called?

1) antiforms 2) synforms

22

state the angle of a
-gentle
-open
-closed
-tight
-issoclinal
fold


-120-180
-70-120
-30-70
-0-30
-0