physical landscapes - glacial landscapes in the UK

Question 1

what is weathering

Answer 1

the breakdown of material where it stands
e.g.freeze-thaw weathering

Question 2

describe the process of freeze-thaw weathering

Answer 2

•water seeps into cracks in a rock face (may be water from summer rainfall or snow melt)
•water expands by 10% when it turns to ice, this expansion puts pressure on the rock either side of the crack, prising it apart and causing the crack to tear open
•process repeats and over time, large blocks of rock can be shattered apart by repeated cycles of this weathering process

Question 3

what is the name for the fragments of rock broken away from the mountainside via freeze-thaw weathering

Answer 3

scree

Question 4

where are glaciers formed

Answer 4

They are formed in areas of high snowfall in winter and cool temperatures in summer. This means that the snow that accumulates in the winter isn’t lost by melting or evaporation during the summer. These conditions occur in polar and high alpine regions. Usually on north facing mountains.

Question 5

describe plucking

Answer 5

when meltwater beneath a glacier freezes and bonds to the base of the glacier to the rocks below as the glacier moves it plucks these rocks leaving behind a jagged landscape

Question 6

describe abrasion in glacial erosion

Answer 6

•sandpaper effect caused by the weight of the ice scouring the valley floor
•it leaves a smooth polished surface
•striations (sharp grooves) caused by large rocks beneath the ice can often be seen

Question 7

what is bulldozing

Answer 7

when a glacier moves forward it can act like a giant earthmover, bulldozing piles of rock debris in front of it to create a high ridge called a moraine, the furthest advance of a glacier is marked by a terminal moraine, this is because the glacier has a huge mass

Question 8

what’s an arête

Answer 8

an arête is a narrow ridge formed when two corries have eroded back to back making the land between them thinner and thinner

Question 9

how is a pyramidal peak formed

Answer 9

a pyramidal peak is formed when three or more corries erode back to back to form a single peak where the arêtes meet

Question 10

describe the contour lines around a corrie

Answer 10

corries have tightly packed contours in the U-shape around then

Question 11

what are glacial troughs

Answer 11

glacial troughs are flat valleys with very steep sides, there are no contour lines on the bottom of the valley but they’re tightly packed on the sides

Question 12

what are drumlins

Answer 12

they are egg shaped hills, composed of mounds of till, caused by glacial deposition (ice bulldozed down the valley) and can show the direction the ice was travelling in

Question 13

what type of lake could you find in a U-shaped valley

Answer 13

a ribbon lake

Question 14

define lateral moraine

Answer 14

material comes from freeze-thaw weathering of the high valley sides, which is deposited along both sides of the glacier/that runs along edges of a glacial trough

Question 15

define medial moraine

Answer 15

•these are the ridge of rocks running down the middle of the valley formed by two lateral moraines from two glaciers coming together

Question 16

define terminal moraine

Answer 16

rocks deposited in a ridge at the maximum advance of the glacier (material builds up if the glacier stays in the same place for a long period of time)

Question 17

describe how the blunt and tapered end of a drumlin is made

Answer 17

blunt end - glacier meets a bump in land or a big boulder so accumulates and then goes around it
tapered end - some material gets dragged and deposited

Question 18

what have developed on valley floors - give an example

Answer 18

settlements have developed on dry, flat sections of the area’s wide, U-shaped valley bottoms, an example is Kewick, which the River Derwent now flows into

Question 19

draw the steps of how a corrie is made

Answer 19

draw three images:
first image - a high mountain peak with a small dip near the top and show a small glacier forming and some snow
second image - zoom into the small glacier from first image and show cracks forming at the back of the glacier and label it with freeze-thaw weathering, show scree falling from the cracks and into the glacier and at the bottom of it, label the glacier with glacier and then label the backwall and plucking next to the backwall label and abrasion at the bottom of the glacier, label the land at the end of it with reduced erosion as the ice is thinner
third image - label a very steep backwall and draw it, label a pile of scree/scree slope at the bottom of the wall and at the start of the curve, then label much deeper rock basin at the bottom of the corrie and finally label the rock lip

Question 20

describe how corrie is made

Answer 20

can use images
•snow accumulates high up in a hollow and is compressed into ice
•over time the snow becomes glacial ice and there is more ice than the depression can hold and some of it starts to flow to lower levels
•ice becomes frozen to the back of the hollow and plucking occurs as blocks of rock are pulled away as the ice moves downhill. This makes the back wall steeper and these rock fragments become incorporated into the glacier.
• freeze-thaw weathering occurs at the top of the slope producing scree which becomes incorporated into the glacier
• the hollow deepens where the ice is thickest due to abrasion. Rock debris acts as tools to wear away the bottom of the hollow.
• there is less erosion at the front where the glacier leaves the corrie hollow to flow down the valley; a rock lip forms here as a result of less powerful erosion
• When all the ice has melted a tarn (lake) forms

Question 21

what is a landform

Answer 21

a natural and distinctive feature on earth’s surface caused by geographical processes e.g. erosion or deposition

Question 22

what are characteristics and formation of landforms resulting from erosion during the glacial period

Answer 22

corries, arêtes, pyramidal peaks, truncated spurs, glacial troughs, ribbon lakes and hanging valleys

Question 23

how do glaciers move in the summer

Answer 23

meltwater lubricates allowing the glacier to slide downhill, this type of movement can be very sudden and is called basal slip, in hollows high up on the valley sides, this movement is more curved and is called rotational slip

Question 24

how do glaciers move in the winter

Answer 24

the glacier becomes frozen to the rocky surface, the weight of the ice (glacier) and the influence of gravity causes individual ice crystals to change shape in a plastic way, this is called internal deformation and causes the glacier to move slowly downhill

Question 25

what is the opposite of glacial periods

Answer 25

interglacial periods