lithosphere Flashcards

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1
Q

corrie

A

armchair shaped hollow with a steep backwall and rock lip

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2
Q

arete

A

narrow knife edge ridge where two corries cut back into each other

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3
Q

pyramidal peak

A

pointed peak with steep slopes with aretes where 3 or more corries cut back

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4
Q

glacial trough

A

steep sided U-shaped valley that is widened steepened and deepened

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5
Q

hanging valley

A

tributary valley that is left high above the main valley

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6
Q

truncated spur

A

steep cliff like valley sides

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7
Q

ribbon lake

A

long narrow lake in a trough

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8
Q

corrie lochan

A

small deep circular lake within a corrie

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9
Q

glaciation- plucking

A

ice freezes onto solid rock and as the glacier moves it causes pieces of rock to move with it

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10
Q

glaciation- frost shattering

A

a physical weathering process, water enter the joints and cracks in the rock and freezes as it does this it expands putting pressure onto the rock, this slowly causes angular pieces of rock to fall off and can fall down hill making scree slopes

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11
Q

glaciation- abrasion

A

morraine embedded into the base and sides of the glacier wears away the land like sandpaper

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12
Q

how does a glacier form

A

glacier forms facing away from the sun, north facing, snow accumulates which compacts into firn and then becomes glacial ice and becomes angular snow which moves down hill by gravity

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13
Q

what are large quantities of material called on glacier

A

moraine

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14
Q

glaciation- supragically

A

material carried ontop of the glacier

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15
Q

glaciation- englacially

A

material carried within the glacier

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16
Q

glaciation -subglacially

A

material carried underneath the glacier by ice or meltwater

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17
Q

glaciation- drift

A

boulders, sand and clay deposited under special conditions

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18
Q

glaciation- till

A

unsorted material of rocks sand and clay of various sizes are deposited by the glacier. its main features are erratics, morraine, drumlins

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19
Q

glaciation- fluvioglacial material

A

sorted material, main sands and gravel that are deposited by meltwater streams. its main features are eskers, kames, kettles, braided streams

20
Q

glaciation- lateral morraine

A

carried on the surface of the glacier, comes from rockfalls on valley slopes. when the ice melts the material is dumped in a lonh line along the valleyside

21
Q

glaciation- ground morraine

A

material dragged underneath a glacier. when deposited it forms a flat valley floor

22
Q

glaciation- terminal morraine

A

terminal morraine is dumped at the end of the glacier. it forms and arc like ridge across the valley

23
Q

glaciation- drumlins

A

have steep stass side with a mound of glacial fill and a gentle side with a more streamlined appearance. the direction of the ice is parallel to the movement of long axis . drumlins usually occur in groups and are though to be formed when the ice becomes overloaded with material and it was forced to deposit some, streamlining occured by later ice movement

24
Q

formation of a corrie

A

before glaciation- snow accumulates in the north facing hollow and compacts into firn and then glacial ice

during glaciation- frost shattering contributes morraine to the glacier and plucking steepens the back wall.max erosion is where the ice is deepest and the rotational movement of morraine deepens hollow by abrasion and can form a rock lip and bershrund crevace

after glaciation- corrie lochan formed along with a scree slope as frost shattering is still present and morraine acts as a natural dam

25
Q

formation of pyramidal peak and arete

A

before glaciation- a round top mountain is present with shallow depressions

during glaciation- the exposed part of the mountain is shattered by frost shattering and ice eats back into the hill from the corrie by plucking which will cause a ridge between to start to narrow steepen and sharpen

after glaciation- pyramidal peak is formed when 3 or more aretes meet which is formed bwteen two corries

26
Q

formation of glacial trough and hanging valley

A

before glaciation- a v shaped valley with a main river meandering around interlocking spurs is present with tributaries

during glaciation- the main valley glaicer widens deepens steepens and straightens the valley by plucking and abrasion, the tributary valley glacier is smaller so less erosion occurs

after glaciation- steep straight spurs have been truncated a flat valley floor is present usually with a misfit stream, due to differential erosion tributary valleys are left hanging above floor of the main valley

27
Q

formation of terminal morraine

A

as the ice moves, the glacier pushes unsorted and angular debris infront of it. the snout of the glacier can rwmain stationary for long periods of time when melting and accumulation are equal the boulder clay or till is then deposited as a ridge across the valley floor. a series of morraines will occur if the glacier retreats with pauses

28
Q

formation of esker

A

a sinous ridge of sorted and rounded silt, sand , gravel deposited by meltwater frosting in sub-glacial channels or through tunnels of ice

29
Q

how is the size of a wave determined

A

speed of wind, length of time the wind has been blowing, distance of sea it has travelled over

30
Q

coastal-wave pounding

A

steep waves generate great speed as the bit foot of the cliff

31
Q

coastal- hydraulic action

A

as a wave breaks air is compressed into cracks in the rock. the rock is loosened so that fragments are washed off.

32
Q

coastal- abrasion/corasion

A

pebbles are repeatedly picked up from the sea bed and are hurled against the cliff wearing it away

33
Q

coastal-attrition

A

rocks in the wave a rebashed off each other rounded and smooth

34
Q

coastal- salt crystalisation

A

salt water enters pore spaces in the rocks and evaporates leaving crystals behind which out stress on the rock causing it to disintegrate

35
Q

coastal- carbonation

A

rock such as limestones dissolve by slightly acidic water

36
Q

coastal- frost shattering

A

only in exposed cold locations

37
Q

coastal- biological weathering

A

may occur where plants grow on cracks on the rock cliff

38
Q

formation of wave cut platforms

A

form at the foot of the cliff often at a headland where energy is maximum, erosion by abrasion corrosion pounding and hydraulic action result in undercutting the cliff to form a wave-cut notch with overhang above, this continues causing the overhang to collapse, as process repeats the cliff retreats back leaving a gently sloping wave cut platform.
the platform widens overtime and the waves break further out to sea which reduces rate of erosion and limiting growth

39
Q

formation of headlands and bays

A

form where there is differential erosion due to alternate bands of more and less resistant rock, this coastline consists of parallel bands of hard and soft rock which are perpendicular to the sea. due to the differential erosion the bands of soft rock are eroded more quickly than the bands of resistant rock resulting in bays and headlands

40
Q

formation of cave, arch, stack and stump

A

coasts occur where the coastline consists of hard rock and is attacked by waves along a line of weakness such as a joint. they will attack the line of weakness with hydraulic action, abrasion and solution. occasionally a blowhole will be created within the cave where compressed air is pushed upwards by the power of the wave and vertical hydraulic erosion works. overtime horizontal erosion may cut through the headland forming and arch. continual erosion may eventually cause the roof to fall leaving a stack isolated from the cliff. overtime the stack can fall due to erosion leaving a stump

41
Q

formation of longshore drift

A

waves approach the beach at an angle because of prevailing winds, when they break swash carries material up the beach at the same angle. the backwash carries material straight back down the beach. the material then moves in a zigzag pattern and the material becomes more rounded and sorted as it travels.

42
Q

formation of a sand spit

A

a sand spit is a long narrow section of land made of sand which extends at a gentle angle out to sea from the mainland. longshore drift moves sand along the beacj which allows material to be deposited in open water. for this the sea has the be relatively shallow to allow accumulation to occur. it eventually builds up to sea level to form an extension of the beach. as the sandspit becomes longer its rate of growth decreases because the water becomes deeper . wind from different direction can cause sand spit to become hooked.

43
Q

formation of a sandbar and lagoon

A

if a large river drains into an estuary behind a spit it will not cross the mouth as the river current carries materials out to sea. however if there is no major river the spit may continue to grow across the bay to the next headland to form a bar. bars straighten the coastline and trap water in lagoons that cut off supply of sea water, a lagoon is a body of brackish water which often supports specialized plants and animals . the lagoon may evaporate and become filled with sediment becoming salt marsh or dry land

44
Q

tombolo

A

a tombolo is a beach or spit which extends out to reach an offshore island. small tomolos are often only exposed at low tide

45
Q

sand dune

A

sand dunes form along low land coasts where there is a sandy beach and alrge expanse of beach at low tide. with these conditions a low tide onshore wind picks up dry sand and moves it up the beach by saltation, the sand is moved as far as the strandline,