Rejuvenation

Question 1

What are isostatic changes?

Answer 1

Changes in the level of the land in relation to the sea level.

Question 2

What are eustatic changed?

Answer 2

Changes in the sea level in relation to the land level.

Question 3

Rejuvenation causes what two things to be increased?

Answer 3

• The rivers potential energy.

* The rivers capacity to erode (caused by the potential energy increase).

Question 4

When rejuvenation happens, what does a river have to adjust to?

Answer 4

The river has to adjust to its new base level.

Question 5

How does the river adjust to its new base level when rejuvenation is caused?

Answer 5

It does it from the sea and progressively inland.

Question 6

When rejuvenation happens, what FIVE landforms can be caused?

Answer 6

Waterfalls
Rapids
Incised meanders
Knick points
River terraces

Question 7

What is the potential energy of a river?

Answer 7

The amount of energy a river could have, dependent on the altitude of the source in relation to the rivers base level.

Question 8

What are the two types of energy a river can have?

Answer 8

Potential and kinetic energy.

Question 9

Describe what the kinetic energy of a river is.

Answer 9

Generated by the flow of a river, which converts the rivers potential energy into moving energy.

Question 10

Define what river terraces are.

Answer 10

Narrow and flat pieces of ground that run parallel to the river on either side of it and above the current floodplain level. Usually created by a fall in base level.

Question 11

What are river terraces usually caused by?

Answer 11

A fall in base level.

Question 12

Finish the sentence. A river terrace is a remnant of…

Answer 12

A former floodplain thee been left with w higher level after the rejuvenation of a river.

Question 13

Describe the process of a river terrace forming.

Answer 13

When rejuvenation takes place, the river renews its down cutting power and sinks its new Channel into a former floodplain and the old floodplain (river terrace) is left above the present river level.

Question 14

When a river is rejuvenated, what is renewed?

Answer 14

The rivers power of down cutting in the form of vertical erosion power.

Question 15

After terraces have been formed, how can they be cut back?

Answer 15

They can be widened by the river laterally eroding.

Question 16

What can cause terraces to form beneath old river terraces?

Answer 16

Renewed rejuvenation.

Question 17

Renewed rejuvenation can cause what?

Answer 17

More river terraces to form beneath the old ones.

Question 18

Identify a river that has river terraces by several stages of erosion.

Answer 18

The river Thames.

Question 19

Describe two practical human uses for river terraces.

Answer 19

• they can provide practical flood shelter in the rivers lower course.
• can be natural route ways for roads and railways.

Question 20

Describe a place where river terraces have been used as natural tour ways for roads and railways.

Answer 20

The built up areas of Oxford and London are mostly located on the river terraces of the River Thames.

Question 21

Define what an incised meander.

Answer 21

A meander that’s cut deeply into the floodplain of a river, causing steep cliff like banks. The river is formed by river rejuvenation.

Question 22

Describe how the river is left when an incised meander is formed in the river.

Answer 22

The river level is left far below the former floodplain level.

Question 23

What needs to happen for any type of incised meander to form?

Answer 23

A river needs to keep its meandering course as vertical erosion in the river increases.

Question 24

What are the two types of incised meander that can be formed in a river by rejuvenation?

Answer 24

• entrenched meander

* ingrown meander

Question 25

What are the three key features of any valley of an incised meander?

Answer 25

^deep ^steep sided ^wide valleys

Question 26

An ingrown meander is formed when there is _______ incision and _______ erosion.

Answer 26

Slow incision Lateral erosion

Question 27

An ingrown meander has an ___________ valley.

Answer 27

Asymmetrical.

Question 28

Describe the shape of the bends of an ingrown meander.

Answer 28

The outer bends has steep cliffs and re inner bends had a gentler slip off slope.

Question 29

The outer bends of an ingrown meander has _______cliffs whereas the inner bend has a _______ slip off slope

Answer 29

INGROWN MEANDERS Outer bend has steep cliffs Inner bend has a gentler slip off slope

Question 30

What is the nature of the incised meander formed mainly determined by?

Answer 30

The rate at which vertical erosion is ensuing in when rejuvenation of the river takes place.

Question 31

What are entrenched meanders said to look like?

Answer 31

They have a Gorge like appearance.

Question 32

Explain the criteria for an entrenched meander to form.

Answer 32

* rapid incision. * vertical erosion or down cutting dominates. * low level of lateral erosion.

Question 33

An entrenched meander gives a __________ valley.

Answer 33

Symmetrical.

Question 34

What are the shape of the sides of an entrenched meander?

Answer 34

They are steep sided valleys that are more symmetrical than the sides of an ingrown meander.

Question 35

Define what a knick point is.

Answer 35

Usually marked by Rapids, knick points are caused by rejuvenation and are a sudden break in the gradient in the long profile of a river.

Question 36

Most knick points are caused by ________.

Answer 36

Rejuvenation.

Question 37

As well as rejuvenation, what other thing can cause a knick point within a river?

Answer 37

Rock type variation.

Question 38

Some knick points are ______ _______. E.g; waterfalls.

Answer 38

Sharply defined.

Question 39

When are knick pints formed?

Answer 39

Where old and new profiles of the river join.

Question 40

The knick point recedes at a rate that's dependent on what?

Answer 40

The resistance of rock.

Question 41

Explain how a knick point is formed.

Answer 41

When a river rejuvenates, the new base level adjustment begins at the sea and works it's way up the course- the river gains more downcutting power which encourages long poor file adjustment and the KP is formed where the old and new profiles join.

Question 42

Define what rejuvenation is.

Answer 42

An increase in the energy of a river, caused by either a fall in sea level relative to the level of the land (eustatic change) of a rise of the level of the land in relation to the sea level (isostatic change).