coasts- physical processes

Question 1

constructive waves

Answer 1

• 6-9 waves per minute
• calm weather
• less powerful
• deposit material
• long wavelength, low in height

Question 2

hydraulic action

Answer 2

• sheer weight and impact of the water against the coastline
• pockets of air widen cracks
• put under high pressure by the water

Question 3

abrasion

Answer 3

particles carried by the water crash against the cliff

Question 4

attrition

Answer 4

• particles carried by the waves are reduced in size as they collide with eachother and the rock face
• pebbles are broken down into sand sized articles

Question 5

solution

Answer 5

• when salts and other acids in the sea water dissolve certain rock types e.g limestone

Question 6

cliff retreat

Answer 6

• erosion focused between high tide marks creating a wave cut notch
• an overhang is created
• overhang grows until it collapses causing the cliff to retreat
• process repeats
  wave cut platform is left behind

Question 7

headlands and bays

Answer 7

headlands are formed when the sea attacks a section of coast with alternating bands of hard and soft rock
the rocks erode and different rates leaving a section of land jolting out into the sea
the areas where soft rock has eroded away next to a headland are called bays

Question 8

factors that affect the rate of erosion

Answer 8

type of rock:
- hard rock erodes slower than soft rock
characteristics of rock:
- cliffs with joints, faults or bedding planes erode quicker because there are more places for the waves to exploite
arrangement of rock
weather:
- storm conditions are when the highest rates of erosion are recorded

Question 9

longshore drift

Answer 9

• particle is carried up he beach by the swash roughly in line with the prevailing wind
• gravity brings particle back down

Question 10

formation of spits

Answer 10

• when sediment starts to build up away from the coastline because the land changes direction
• fast flowing river stops the spit from going across to the other side of the bank because the river washes away the material
• a salt marsh is formed behind the spit

Question 11

bedding planes

Answer 11

• horizontal beds
• differing rate of erosion
• vertical beds
• uniform resistance to erosion
• sloping beds
• sea ward dipping of bedding planes loose material can slide easily towards the sea

Question 12

bars

Answer 12

if a spit joins one part of the mainland to another it is called a bar
lagoon is formed behind the bar
tombolo- when a spit joins an offshore island

Question 13

destructive waves

Answer 13

• 11- 15 waves per minute
• erode coast
• winter
• created in storm conditions
• short wavelength, steep
• stronger backwash than swash

Question 14

eustatic sea level change

Answer 14

• world wide sea level change that is caused by melting ice caps and glaciers

Question 15

isostatic sea level change

Answer 15

• local or regional relative change in sea level, which is caused by a change in the level of the land
• this may be caused by the land being jolted upwards by tectonic forces or by land that was compressed beneath ice sheets over a mile thick 18,000 years ago rebounding upwards and the pressure is lifted.

Question 16

esturies

Answer 16

• drowned valley
• rising sea levels from glacial ice melt, flood the broad, flat flood plains of rivers, creating wide shallow, salt water, tidal river mouths

Question 17

Fjords

Answer 17

• drowned glacial valleys
• steep, narrow, rock walled sides
• very deep
• carved out by glaciers- found in the west of norway

Question 18

Ria

Answer 18

• this is a drowned unglaciated river valley
• dendritic in shape
• large mouth for a small river e.g. milford haven

Question 19

raised beach

Answer 19

• falling sea level leaves the old beach raised above the new, present day shoreline
• this may have an old cliff line behind the beach, this is called a relic cliff