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Discordant coastline can also be referred to as?
atlantic coastlines
Concordant coastline can become what types of coastlines?
Haff and Dalmatian coasts
Example of a concordant coastline in UK
Lulworth cove on the Jurassic coast
Harder rock in Lulworth cove
Portland limestone
Softer rock in Lulworth cove
Wealden clay
How was the Dalmatian coast in Croatia formed
through tectonic forces and sea level rise
(that caused the submergence of land and the formation of a series of islands and coastal inlets.)
(folding of the plate caused anticlines and syclines (when it folds the land upwards and downwards, respectively —— to ~~~ the up hump is anticline and down dip is sycline)
where is a haff coastline?
southern baltic coast
what type of coastline is the Jurassic coast?
East = discordant
south = concordant
Name coastal erosion processes
Hydraulic action
Abrasion
Attrition
Corrasion
Name the transportational processes
Traction (rolling rocks along the bottom)
Saltation (skipping rocks along bottom)
Suspension
Solution
strata
layers of rock also known as beds
bedding planes
horizontal cracks/lines between the different strata
(surface that separates one strata and another)
created by the pauses in rock formation
joints
vertical cracks in the rock caused by tectonic movement or contraction
Folds
the result of pressure during tectonic movement causing the rock strata to fold
Faults
the result of stress or pressure on the rock causing to fracture
Dip
The angle of the rock strata
Sub-aerial processes
weathering
mechanical (physical)
chemical
biological
mass movement
sliding (mudslide or landslide)
slumping
rockfall
Mechanical (physical) weathering examples
Thermal expansion(heating and cooling of the rock in general)
frost weathering/wedging (water seeps into cracks then expands when it turns into ice over night)
Salt weathering. (salt water gets in rock, water evaporates leaving salt crystals behind (accumulates adding more pressure))
exfoliation (curved plates of rock are stripped from rock below)
By how much does water expand when frozen/turned to ice?
by 10%
Chemical weathering
bodily fluids from animals (feces and urine)
solution/carbonation (slightly acidic carbonic rain it reacts with the calcium carbonate - affects rocks like limestone and chalk)
Oxidation (when rocks are broken down by oxygen and water.)
Hydrolisis (chemical breakdown of a substance when combined with water)
Biological weathering examples
animals burrowing in the ground
Plant roots weakening the rock
humans eroding it by walking all over it
mass movement
when rocks and loose material shift down slopes. This happens when gravity overcomes the force supporting the material.
Where permeable rock over lies impermeable rock, the permeable rock is vulnerable to mass movement because the additional weight and lubrication the water creates leads to instability
Difference between sliding, slumping and rockfall
Slides - rock moves in a straight line
Slumps are when material moves down a slope with a rotation. (cliff gets saturated with water and base is eroding (maybe wave cut notch)and slumps
Rock falls are when material breaks apart because of erosion and weathering and then rolls down a slope.
Wave refraction and how it affects the coastline
waves bend as they hit the coastline at an angle, causing uneven distribution of energy and significantly influencing coastal shaping through erosion and deposition
How can mineral composition affect erosion?
Some minerals are more reactive than others which affects the rate of chemical weathering
Examples:
Quartz (inert) not reactive so chemical erosion is slower
Calcite is very reactive so erodes much quicker
How are sedimentary rocks formed?
formed from compaction and cementation of sediment called lithification
Examples of sedimentary rock
shales, sandstone and limestone
Properties of sedimentary rocks
erode and weather more rapidly
form in layers
have weak bedding planes
they are clastic
meaning they are made of clasts (sediment particles)
heavily jointed
often have many bedding planes and fractures
How are metamorphic rocks formed?
Sedimentary and igneous rocks are altered through heat and pressure but do not melt in the process
Examples of metamorphic rocks
slate and marble
Properties of metamorphic rocks
crystalline structure
often folded and faulted
more resistant the sedimentary
crystals have parallel arrangement (foliation) which means they are weaker than igneous
How are igneous rocks formed
molten rock from volcanoes cools and hardens
Examples of igneous rocks
granite and basalt
properties of igneous rocks
most resistant
can be categorized into 2 types
intrusive - form within the ground, cool slowly and have large course crystals
extrusive - form on the earths surface, cools quickly, forms smaller crystals
has interlocking crystals
making it harder than metamorphic
fewer joints and weaknesses than other rocks
what is differential erosion?
changing/differing rates of erosion along a coastline
the whole coastline doesn’t erode at the same rate
headlands and bays are an example
bay erodes quicker than the headland
How can differential erosion affect coasts lines?
leads to headlands and bays on discordant coastlines
alternating strata can create a cliff profile where they more resistant rock juts out
alternating permeability
permeable is on the top can be at risk of mass movement because of added weight and lubrication