folding and faulting

Question 1

what is a fold

Answer 1

A bend or curve in the rocks of the Earth’s crust

Question 2

define compression

Answer 2

When two continental plates collide, land is forced or folded upwards through the process of Compression

Question 3

explain the difference between the lithosphere and asthenosphere

Answer 3

The lithosphere compreises of the solid upper mantle and crust. whereas the asthenoshphere comprises of the most upper part of the liquid lower mantle

Question 4

what is menat by oregency

Answer 4

Refers to mountain building processes. This occurs due to tectonic movements that causes plates to buckle upwards, forming fold mountains.

Question 5

what is a fault

Answer 5

A crack or fracture in the Earth’s crust

Question 6

what is a limb

Answer 6

the sides of the fold

Question 7

what is a simple fold

Answer 7

Simple Fold: This fold has two limbs of equal steepness

Question 8

what is an assymetrical fold

Answer 8

: One limb is steeper than the other in this fold because greater compression is applied to one side of the fold than the other.

Question 9

what is an overfold

Answer 9

When compression from one side is much greater, one limb is pushed over the other limb.

Question 10

what is a recumbent fold

Answer 10

s the compression continues, the folds eventually lie almost horizontally on top of one another

Question 11

what is an overthrust fold

Answer 11

Finally, the compression force is so great that the

rock strata fracture (fault) and one limb is pushed up and over the other limb.

As a result, the strata are no longer continuous.

Question 12

what are the periods of folding which affected the irish landscape

Answer 12

armorican and caledonian

Question 13

how long ago was the caledonian orgenency

Answer 13

400 million ya

Question 14

how long ago was the amorican oregency

Answer 14

250 million ya

Question 15

why did the calendonian orgency take place

Answer 15

Took place when the North American and Eurasian plates collided.

Question 16

why did the amoricann orgency take place

Answer 16

This fold mountain period occurred when the African and Eurasian plates collided.

Question 17

what mountaisn did the caledonian orgency form

Answer 17

wicklow mountain

Question 18

what period of orgency formed the muster ridge and valley

Answer 18

armorican valley

Question 19

what direction do the caledonian mountaisn run

Answer 19

north east to south west

Question 20

what is the oldest ,mountains

Answer 20

caledonian

Question 21

what kind of rock formed duting the caledonian period

Answer 21

magma intrused cracks in fold and cooled slowly to form igenous rocks

it also cam ein contact with sedimentary rock changing it into metamorphic rock eg marble and quartz

Question 22

did metamorhpic rock from the caledonaian period from a protetcive cap on some mountains?

Answer 22

yes, it formed a protetcive cap on the sugarloaf in co wicklow and croagh patrick in co mayo

Question 23

what are the oldest mountain in ireland and what kind of height are they

Answer 23

caledonian and they are the smallest now around 600-700m due to weathering and erosion

they were once 4,000m

Question 24

what places are caledonian mountains found that arent in ireland

Answer 24

scottish highlands, greenland an dnorth america

Question 25

what direction does the armorican mountaisn run

Answer 25

east to west direction comeraghs to macgillycuddy reeks

Question 26

what kind of ridges have formed in the armorican mountaisn due to weathering and erosion

Answer 26

the anticlines used to be limestone but that has eroded away to form caps of sandstone

Question 27

what kind of valleys have formed in the armorican mountaisn due to weathering and erosion

Answer 27

the syncline sof limestone were not weathered as uch as the anticlines so there are now valleys of limestone

Question 28

what rivers flow through the armorican mountains/ridges

Answer 28

river lee and bandon flow through limestone valleys

Question 29

what is the height of the armorican mountains

Answer 29

highest in ireland they were not as high as the caledonian but are now eg carruntohill in kerry is 1037m

Question 30

what is a recent oregncy that occured outside of ireland

Answer 30

alpine oregency occured 60 milllion ya

Question 31

explain how the alps were formed by the alpine orecgeny

Answer 31

collision of the african na d eurasion plates 30 million ya both continental plates formed mountaisn 4000m high

Question 32

what happned to form the Himalayas

Answer 32

formed 50 million ya when the indo-austarlian plate and the eurasion plate collided more than 8000m high

Question 33

how did the andes form

Answer 33

formed 50 million ya when the pressure form the subdicting nazca plate caused the overlying south american plate to buckle mountaisn over 6000m high

Question 34

what are the processes of faulting

Answer 34

tension compression shearing

Question 35

what is tension

Answer 35

tension is where rocks are pulled apart

Question 36

what is compression

Answer 36

is is where rocks are psuhed together from both sides

Question 37

what is shearing

Answer 37

layers of rocks move sideways in opposite directions

Question 38

what type of fault does tension form

Answer 38

normal fault

Question 39

what type of fault does compression form

Answer 39

reverse fault

Question 40

what type of fault does shearing n form

Answer 40

transform fault

Question 41

what is a scarp

Answer 41

cliff formed by the vertical displacement of rock

Question 42

what is a throw in terms of faults

Answer 42

it is the disctance the crust has move dup or down

Question 43

what is a heave in terms of faults

Answer 43

is the hormizontal movement of rock

Question 44

what is the hanging wall

Answer 44

section of rock that moves

Question 45

what is the section of rock called in a fualt that doenst move

Answer 45

footwall

Question 46

how is a tranform fault formed

Answer 46

sideways moveemnt of crust

Question 47

how is a normal fault formed

Answer 47

tension- rocks break hanging wall slides down and footwall remains elevated

Question 48

how is a reverse fault formed

Answer 48

compression- crust fracture hanging wall slides upwards above footwall

Question 49

give an example of a transorm fault

Answer 49

san andreas fault- north american and pacific plate slide past each other

Question 50

what landfrom does a reverse fault form

Answer 50

block mountain eg ox moutains in sligo

Question 51

what landform does a normal fault form

Answer 51

rift valley eg east african rift valley and devils gap in sligo

Question 52

how are monoclines formed

Answer 52

small earth movemtns sedimentary rock is compressed and uplifted slightly

Question 53

give an ecample of an irish monocline

Answer 53

ben bulben in co sligo

Question 54

what causes doming

Answer 54

it is caused by pressure from rising magma which builds pressure under sedimentary rock causing it to bulge upwards or rocks being compressed from several directions

Question 55

give an example of doming

Answer 55

slieve bloom moutain rnage

Question 56

oldest strata are are where in relation to the centre of a dome

Answer 56

in the centre