4 - factors affecting coastal processes/landforms

Question 1

what is fetch and how does it influence a coastline

Answer 1

FETCH - maximum distance that wave travels in one direction

long fetch = maximised coastal erosion as produces waves with greater energy

Question 2

how does wave type impact formation of coastal landforms

Answer 2

CONSTRUCTIVE - stronger swash, weaker backwash and build up beach over longer time

DESTRUCTIVE - weaker swash, stronger backwash and destroy beaches over short periods of time

Question 3

how does wave orientation influence formation of landforms

Answer 3

• direction waves come from impact effectiveness in shaping coastline
• prevailing wind most common direction
• different weather systems = wind blowing waves from different directions, increasing/decreasing rates of erosion accordingly

Question 4

how does wave refraction influence formation of landforms

Answer 4

• energy focused on headlands creating destructive activity, and deposition in bays, influencing shape of coastline
• wave refraction = speed of wave reduced and shape of wave front altered
• wave fronts break parallel to shore and refraction distributes wave energy along stretch of coast

Question 5

what is the clapotis effect

Answer 5

along rocky coastlines there is a deep offshore platform and waves are reflected back from cliff

waves don’t break at shoreline so rates of cliff recession are decreased

Question 6

what is coastline lithology

Answer 6

= makeup of rocks present

number of factors interacting to influence lithology of coastline

Question 7

how does rock hardness influence the coastline

Answer 7

• igneous/metamorphic rocks more resistant to erosion than sedimentary, as heating/compression involved in their formation

Question 8

how does chemical composition influence the coastline

Answer 8

• minerals and solubility

- chemically inert rocks have low rates of chemical weathering

Question 9

how does permeability influence the coastline

Answer 9

pores in open textured rock (limestone) or fissures and joints (chalk) allow surface water to seep into cliffs
increases rocks resistance to subaerial weathering and adds strength to softer rocks

Question 10

what is a discordant coastline

Answer 10

most common coastline, geology perpendicular to coast so differential erosion causing headlands and bays

Question 11

what is a concordant coastline

Answer 11

alignment of rocks runs parallel to coast

features such as caves/bays formed but differences in character

Question 12

what is structural geology

Answer 12

coastal cliffs containing joints, bedding planes, folds and faults which impact upon rates of weathering/erosion and formation of landforms

dip of rock beds determining degree of exposure to weathering and erosion

Question 13

how does a joint influence the coastline

Answer 13

JOINTS = blocks of rock in cliffs (bricks that have gaps between them)

more jointed rock is = easier for waves/water to enter and exploit lines of weakness (erosion/weathering)

Question 14

how does a bedding plane influence the coastline

Answer 14

BED - division of geological formation or stratigraphic rock marked by divisional planes (bedding planes) separating it from layers above/below

serve as lines of weakness, can be exploited by erosion/weathering

Question 15

how does a fault influence the coastline

Answer 15

FAULTS = cracks/lines opened up in cliff caused by physical events (tectonic shift, mass movement, weathering, erosion)

exploited by processes of weathering, erosion

Question 16

what is folding

Answer 16

rocks are stretched/compressed by earth movements leading to them folding

2 main types of folding =
anticlines - fold curves upward, older rocks at centre
synclines - fold curves downwards, older rocks at flanks