coasts EQ2 Flashcards

Question

what are the two forms of deposition?

Answer 1

gravity settling and flocculation

Answer 2

type of deposition where the energy of transporting water becomes too low to move sediment. Large sediment will be deposited first followed by smaller sediment

Answer 3

a depositional process that is important for very small particles such as clay, which are so small they remain suspended in water. Clay particles clump together due to electrical or chemical attraction and become large enough to sink.

Answer 4

Beaches are accumulations of sand and/or shingle found in the foreshore and backshore zones. Produced by material deposited by constructive waves. Swash has the strength to carry material up the beach, but backwash only has enough energy to transport some material back down the beach, leaving the remainder deposited.

Answer 5

form where the coastline changes direction and longshore drift continues to move material along the beach in the original direction. LSD will deposit material in the sea after the coastline has changed direction. Over time the level of the sand deposited will build-up until it is above sea level. The seaward end is called the distal end

Answer 6

Occurs as wave refraction round the distal end transports and deposits sediment for a short distance in the landward direction. It could be because the wind and wave front are frequently at an opposing angle to the prevailing wind, generating short periods of longshore drift in the landward direction. Or, a strong incoming tidal current can also create a recurved spit.

Answer 7

form when sediment is transported on and off a beach. Destructive waves remove sediment from the beach and form the offshore bar. Constructive waves transport material from the offshore bar back onto the beach. ridges of sand or shingle running parallel to the coast in an offshore zone.

Answer 8

where spits are joined to the mainland at both ends, trapping water behind in a lagoon

Answer 9

formed by wave refraction and diffraction. As waves near an island, they are slowed by the shallow water surrounding it. These waves then bend around the island to the opposite side as they approach.

Answer 10

found on coastlines that are created primarily by longshore drift. Formed by accumulation and progradation of sand and shingle, they extend outwards from the shoreline in a triangular shape.

Answer 11

Plant succession such as in salt marshes and sand dunes binds the loose sediment together and encourage further deposition. Vegetation can help to trap and stabilise the sediment to make it stronger against the wind and waves.

Answer 12

where sediment is made, cliffs or eroding sand dunes. Some sources are offshore bars and river systems and these are an important source of sediment for the coast. For example cliff erosion, currents onshore, wind blown (aeolian) sediment from land, river transport, marine organisms, and subaerial processes.

Answer 13

sediment moving along; swash, backwash, tidal currents, sea/ocean currents, longshore drift, wind (onshore, offshore or along shore)

Answer 14

where the dominant process is depositional landforms are created, including spits and offshore bars. Some examples of sinks are backshore depositional landforms (sand dunes), foreshore depositional landforms (beaches), nearshore depositional landforms (bars), offshore depositional landforms (barrier islands)

Answer 15

portland bill to selsey bill south england

Answer 16

Selsey Bill is sedimentary bedrock: sand, silt, and clay. This rock is easily eroded. Portland Bill is also sedimentary, made of limestone. The geology at Selsey bill is less resistant than at Portland Bill.

Answer 17

freeze thaw weathering salt crystallisation

Answer 18

mechanical weathering: when water enters a crack or joint in the rock when it rains. And then freezes, the water expands by 10% this expansion exerts pressure and widens the crack. Fragments of rock break away forming scree.

Answer 19

mechanical weathering: when salt water evaporates it leaves salt crystals behind. These can grow and exert pressure on the rock so it breaks up

Answer 20

hydrolysis oxidation carbonation

Answer 21

chemical weathering: occurs when water reacts with minerals in the rock causing the chemical composition of the rock to change and become more unstable.

Answer 22

chemical weathering: rain absorbs carbon dioxide from the air to form a weak carbonic acid. This reacts with calcium carbonate in rocks like limestone and chalk to form calcium carbonate, which is easily dissolved.

Answer 23

chemical weathering: occurs when oxygen reacts with minerals such as calcium and magnesium to form iron oxide

Answer 24

plant roots and rock boring

Answer 25

biological- plant roots start to grow into small cracks in a cliff face. These cracks widen as the roots grow thicker, this breaks up the rock

Answer 26

biological: when animals can move rocks to the surface where they are open to weathering. Animals like limpets also secrete chemicals causing rocks to dissolve. Birds and animals dig burrows into cliffs. Water which runs through decaying vegetation becomes acidic and increases chemical weathering

Answer 27

Mass Movement: material is moved due to gravity. The downslope movement of rocks and soil from the cliff top under the influence of gravity. Mass movement can provide an input of material to the coastal system, which is carried away by waves and deposited further along the coast.

Answer 28

SLIDE mass movement occur when strong, jointed and steep rock faces are exposed to mechanical weathering. Rock falls occur on slopes over 40 degrees. Material once broken away from the source forms scree or talus at the foot of the slope. Block falls are when larger blocks of rock fall away as a single place.

Answer 29

SLIDE mass movement Rocks that are jointed or have bedding planes roughly parallel to the slope are susceptible. Increase in water can reduce friction causing sliding. In a rock or landslide, slabs of rock can slide over underlying rocks along a slide or slip plane

Answer 30

slide mass movement Pieces of rock or cliff face fall forward as large blocks due to forward rotation down a slope. Occurs around an axis at the base of the block of rock.

Answer 31

SLIDE mass movement a downslope movement of material that occurs along a distinctive planar surface of weakness such as a fault, joint or bedding plane

Answer 32

SLIDE mass movement a downslope movement of material that occurs along a distinctive planar surface of weakness such as a fault, joint or bedding plane

Answer 33

FLOW mass movement Occur when the material behaves more like a liquid or fluid due to a high water content and unconsolidated material which causes slope material to lose cohesion, turning it into slurry.

Answer 34

FLOW mass movement Slowest form, a continuous process of downhill movement of individual soil particles.

Answer 35

the angle of the slope, the rock’s lithology and geology, the vegetation cover on the cliff face, the saturation of the ground/ previous weather patterns.

Answer 36

FLOW mass movement Between 5 cm and 100 cm annually. Mainly in tundra areas where ground is frozen- surface layer becomes saturated and flows over the frozen subsoil and rock

Answer 37

loss of businesses from tourism loss of land land unstable or unsafe buildings to collapse injury death

Answer 38

mass movement landform. looks like a fresh curved unweathered and unvegetated rock surface on a cliff face. Left behind from rotational slumping. When heavy rain is absorbed by unconsolidated material, it makes up the cliff. The cliff face becomes heavier and unstable so it separates from the material behind at a rain-lubricated slip plane. The surface of the rupture is curved concavely upward.

Answer 39

Talus is the unstable steep mountain slope composed of rock fragments and other debris. It is material that has accumulated at the base of a projecting mass of rock, or talus slope.