Folding and Faulting definitions

Question 1

Alpine folding

Answer 1

The youngest period of mountain building that occured about 50 million years ago. Still active today. Alpine mountains include the Alps, Himalayas, Andes, Rockies and Atlas Mts

Question 2

Anticline

Answer 2

An up fold of a rock layer

Question 3

Asymmetric fold

Answer 3

A fold in which the limbs are unequal in length and the axial plane is tilted to one side

Question 3

Armorican folding

Answer 3

A long period of mountain building that occured about 300 million years ago. The trend of mountain ranges runs from East to West

Question 4

Block Mountain/horst

Answer 4

A mountain formed by the uplift of a block of rock between 2 faults

Question 5

Caledonian folding

Answer 5

The oldest period of mountain building that occurred about 400 million years ago. The mountains trend from North-east to South-west

Question 6

Fault

Answer 6

A crack in a rock along which the ground moves

Question 7

Fault scarp

Answer 7

A cliff or steep slope formed hen ground is uplifted or sinks along a fault in the earths crust

Question 8

Fold

Answer 8

A bend in a layer of rock

Question 9

Geosynclines

Answer 9

A huge long hollow in the earths crust into which thick layers of sediment are deposited

Question 10

Normal fault

Answer 10

A fault where the hanging wall has moved downward relative to the footwall of a fault. Normal faults are caused by 2 blocks of rock being pulled apart

Question 11

Old Red Sandstone

Answer 11

Thick sequence of rocks (formed 300-400 million y.a) that formed from sediments originating on land. Found in the north-western Europe, Scandinavia, Greenland and Canada

Question 12

Orogeny

Answer 12

A period of mountain building caused by colliding plates

Question 13

Overfold/recumbent fold

Answer 13

This fold has one limb pushed over the other limb, until the axis of the fold is almost horizontal and the two limbs are almost parallel. This is formed when pressure from one side is much greater than from the other side

Question 14

Overthrust fold

Answer 14

A type of overfold where the forces of compression are so great that the fold breaks and the overlying limb moves over the limb below

Question 15

Plate compression

Answer 15

When 2 plates collide

Question 16

Reverse fault

Answer 16

A fault in which the hanging wall moves upward relative to the footwall. They are formed by 2 blocks of rock being pushed together

Question 17

Rift valley/graben

Answer 17

A valley formed when a block of land sinks between 2 parallel faults

Question 18

Symmetric fold

Answer 18

This type of fold has 2 limbs of equal steepnedd. It results when the 2 oppsoing forces moving towards each other are of equal strength. The fold axis is vertical.

Question 19

Syncline

Answer 19

A down fold in a layer of rock

Question 20

Tear/transform fault

Answer 20

A fault where 2 blocks of rock move sideways relative to each other

Question 21

Tension

Answer 21

A force pulling rocks apart

Question 22

Thrust fold

Answer 22

A low angle fault

Question 23

Trend

Answer 23

The direction along the crest of a fold