Coasts EQ1 Flashcards
What is meant by the littoral zone?
wider coastal zone including coastal land area
What are the 5 divisions of the littoral zone?
coast, back shore zone, foreshore,nearshore,offshore
What is meant by the back shore zone?
above high tide level and only affected by waves during high tides
What is meant by foreshore?
where wave processes occur between the high and low tide
What is meant by nearshore?
shallow water areas close to land
Why is it that the zone is constantly changing?
interaction between the short and long term processes operating on it
A) What short-term processes are operating in the littoral zone?
B) long term?
A) tides, waves
B) sea level, geology
How many sediment cells divide the coast of England and Wales?
11
Why is it useful to divide the coast into sediment cell sections?
to improve coastal management
What are the two main types of coasts?
rocky (high and low relief), coastal plains (sandy and estuarine)
What are the two formation processes coasts?
Primary : land-based processes e.g deposition at the coast
Secondary : marine erosion or deposition
What are the 4 different coastal classification systems?
Formation processes
relative sea level change
tidal range
wave energy
What are the two types of coasts with regards to sea level change?
emergent coasts : coast is rising relative to sea level e.g as a result of tectonic upthrust
submergent coasts: being flooded by the sea either because of sea level rise and/or subsiding land
How are rocky coasts created?
high relief, resistant geology often in a high energy environment
How are coastal plains created?
low land and low energy, sediment deposited at the coast causing coastal accretion (deposition of sediment at a coast that expands the area of land)
What is meant by strata?
different layers of rock exposed in a cliff
What two types of coasts are produced by geological structures?
concordant and discordant
a) Describe the structure of a discordant coast
b) concordant coasts
a) different rock strata intersect the coast at an angle
b) rock starta run parallel to the coast
How has geological structure influenced coastal morphology on discordant coasts?
headlands and bays
How has geological structure influenced coastal morphology on concordant coasts?
Dalmatian and haff coasts
What is a Dalmatian coast? (Croatia)
formed as a result of a rise in sea level where valleys running parallel are flooded ad tops of ridges are exposed
What is a Haff coast? (Baltic Sea)
long spits of sand and lagoons aligned parallel to the coast
What are bedding planes?
horizontal cracks , natural breaks in strata caused by gaps in time during periods of rock formation
What are joints?
vertical cracks, fractures caused either by contraction as sediments dry out or by earth movement during uplift
What are folds?
formed by pressure during tectonic activity which makes rocks buckle and crumple
What are dips?
refers to angle at which rock strata lie
What two characteristics of cliff profiles are most dominant?
resistance to erosion of rock
dip of rock strata
True or false: dip is a tectonic feature
True
Give two cliff profile type examples
horizontal dip, seaward dip high angle
What are fissures?
much smaller cracks in rocks
What are the location of micro features within cliffs such as caves often controlled by?
location of faults and/or strata with joints and fissures
What are the three rock types in order of slow to fast erosion rates?
igneous, metamorphic, sedimentary
Describe igneous rock and give 2 examples
result of tectonic activity, often contain crystals
granite, basalt
Describe metamorphic rock and give 2 examples
formed from extreme heat and pressure
slate , marble
Describe sedimentary rock and give 2 examples
made of small particles of rock
sandtone, limestone
True or false: where the rock forming cliffs is unconsolidated material (such as boulder clay), rates of recession can be much smaller?
False, much GREATER
List 4 things erosion and weathering resistance are influenced by
how reactive mineral in the rock are
whether rocks are clastic (particles cemented together) or crystalline(interlocking mineral crystals) (more resistant)
degree to high rocks have cracks
permeability
Give 2 ways in which vegetation stabilises coastal sediment
roots bind particles together
when submerged, plants provide a protective layer
protection from wind
What are halophytes and xerophytes?
halophytes = salt tolerant (salt marshes) xerophytes = drought tolerant (sand dunes)
Pioneer plants species grow w in the bare sand or mud in the first stage of plant succession, describe the pioneer plants of sand dunes
embryo dunes = thick , fleshy leaves to store water
hairs and low density strata to reduce transpiration
What is the name of the pioneer plant in salt marshes?
eelgrass
Why are estuarine areas ideal for the development of salt marshes?
sheltered from strong waves,
rivers transport supply of sediment to river mouth
What is a climatic climax community?
biological community
What is humus?
organic component of soil formed by decomposition
