1
Q
What are some examples of physical/ mechanical weathering
A
- Salt water crystal growth ( SALT CRYSTALS GROW WHEN SEA WATER COLLECTS IN CRACKS THEN EVAPORTES AS THEY GROW, CRYTALS EXERT PRESSURE ON THE ROCKS)
- Freeze thaw (CAUSES CRYSTAL GROWTH)
- Wetting and drying9
(EXPANSION AND CONTRATION OF MINERALS)
2
Q
Examples of biological weathering
A
- Animal droppings
- Plant roots
-Burrowing animals - Marine animals drilling into rocks
- Seaweed pulling rocks of the seabed
3
Q
Examples of chemical weathering
A
- Acid rain
- Carbonation
- Carbonic acid
-Chelation
-Oxidation and reduction - Hydration
- Hydrolysis
4
Q
What is chelation
A
- Organic acids produced by plant roots and decaying organic matter bind to metal ions, causing weathering.
5
Q
What is hydration
A
- Minerals absorb water weak weakening their crystal structure. Rocks are then more suspectable to weathering processes
6
Q
What is hydrolsis
A
- Reaction between mineral water related to the hydrogen ion concentration of water particularly affects the feldspar minerals in granite
7
Q
What is solution
A
- Solubility of minerals depends on the temperature and acidity of the water.
- Limestones are often affected by carbonation although they are less soluble in sea water.
- Spray charged with carbonic acid leads to honey comb weathering.
8
Q
What is weathering
A
- The breakdown of rocks in situ by physical, biological or chemical means
9
Q
What is the key influence on the type and rate of weathering
A
- The climate, and geology
10
Q
What rocks are most at risk for weathering
A
- Porous as water can get inside the rocks
11
Q
What rocks types are going to be most likely effected by wetting and drying
A
Clay and shale
12
Q
Define mass movement
A
- The downslope movement of material under the influence of gravity
13
Q
What does the speed of mass movement depend on
A
- The gradient and the water content
14
Q
How might the presence of water influence the mass movement what season is mass movement most likely to occour
A
- More water = more likely to slip as the land is less bound together and less stable
- Water weakens the soil, and gravity causes the land to slide over each other due to the reduced friction from the water.
- water adds weight
- Winter due to the increase in wet weather
15
Q
what are the 5 main types of mass movement
A
- Rock fall
- Rock slides
-Rock toppling - Rotational slides and slumps
-Creep
16
Q
What causes rock fall and what is it
A
- Blocks of rock are dislodged by weathering (freeze-thaw) and fall to the base of the cliffs
17
Q
What is a Rock slide and what causes it
A
- Blocks of rock slide down the cliffs, especially when rocks are facing steeply towards the sea lubricated by water due to heavy rainfall and additional weight gravity acts upon it to slide it down to the ocean
( common in Carniferous limestone)
18
Q
What is Rock toppling and what causes it
A
- Blocks or even columns of rock (weakened by weathering), fall into the sea
- Common in columnar basalt.
19
Q
What are rotaional slips and slumps and how are they caused
A
- Sections of the cliff give way along a well defined concave slip surface.
- Often composed of clays
- Caused by water saturation and gravity leading to lubrication and a critical threshold is reached triggering the mass movement.
- Occurs when permeable rock overlays impermeable rock
20
Q
What is creep and why is caused
A
- Creep is the extremely slow movement of regolith (The loose material including soil above the bedrock)
21
Q
What is solifluction
A
- the slow downslope movement of regolith, saturated by the melting of the active layer of permafrost (partially frozen layer of soil or sediment below 0 degrees)
22
Q
What are the marine erosional processes 6
A
- Hydraulic action
-Abrasion - Attraction
-Corrosion - Corrasion
- Quarrying
23
Q
What is hydralic action
A
- Erosion due to the force of hydraulic pressure in structural voids that leads to the weakening and readying of the rocks for further wave action
24
Q
What is quarrying
A
- Wheer powerful waves remove loose blocks
25
What is attrition
- The rubbing and banging of loose material against each other, creating more rounded blocks and reducing there size
26
What is Corrasion
- When the wave uses the broken off material provided by attricition and abrasion as tools to futher errode the rock
27
What is corrosion
- Occurs when limestone is chemically attacked by waves
28
What is abrasion
- The scraping of one rock against each other
29
What is the rate of errosion determined by
- The strength of the waves
- The Height of the waves
- Material from the cliffs
- Lithology
- Coastal structure
- Rock structure
30
What is a cliff defined as
- any coastal slope affected by marine prsesses
31
Draw a detailed diagram of a cliff profile and the formation of a shore platform
32
What is the cliff profile determined by
- geology of the cliff
- Balance of marine erosion and sub aerial prosseses
- Inherited charecteristics
33
Why is geology important in the cliff profile and how it affects the cliff's profile
- Harness and softness of rock
- Hard rock forms tall cliffs
- Soft rock forms low-angle cliffs
34
How does the balence between marine errosion and subaerial prosesses have an impact on cliff profile
-Energetic waves eroded the cliffs strongly and also removed debris from the cliffs created by wave erosion, which increases the wave erosion. As piles of sub-areal debris tend to protect the cliffs that dissipate wave energy, protecting the cliffs
35
Why are inherited characteristics important in the cliff profiles
- The sea may rework steep slopes initially formed by non-marine processes under different sea level situations. For example, some plunging cliffs that rise abruptly from Deepwater fjords, were originally sides of submerged glaciated valleys.
36
Describe the prosses of cliff retreate you may use a diagram
- Wave cut notch formed by wave quarrying and corrosion at the base of the cliff which undermines it and makes it less stable. Causing vertical cliff collapse ( hard rock) or slope failure via slumping ( soft rocks) then the debris will be removed and the cliff will retreat leaving behind a wide shore platform.
- The cliff eventually retreats to the place where they are no longer in reach of marine action other than highest spring tides and storm waves. so overtime it becomes "degraded".
37
What are the key causes of cliff regression
- Removal of debris by the waves
- Biological factors
-Beach erosion
- weathering
-Earthquakes or seismic activity
- undercutting
- Groundwater change
- Coastal forcing ( winds, waves, water levels, currents and tides
- Slope forcing
- Precipitation
- temperature
- Human activity (pore water pressure, slope profile)
38
How far do limestones regress every year
- 1 cm
39
What processes are important in the creation of shore platforms?
- by wave quarrying, abrasion, bio weathering and salt water weathering.
40
What angle do shore platforms slope
- 1-5 degrees seaward
41
How are headlands and bays fromed
- Differential erosion of juxtaposes rocks of varying resistance.
42
What type of coastline are headlands and bays formed from
- Concordent
43
How are blowholes created
- Hydralic action
- Air and water are forced into the cave when the wave collides with the rocks. This wave action can develop weaknesses in the rooves of the caves creating vertical shafts and tunnels to the ground surface to form a blow hole. High tides or storms lead to greater pressure.
44
What happened if a blow hole roof collapses what does it form
- A geo or an inlet and if further erosion takes place a narrow gully will form
45
example of a blow hole
-Sprouting horn in Hawaii
46
The sequence of the formation of crack - Stump
-Headland will have a fault or line weakness that will be taken advantage of by the wave action and hydralic power this line of weakness will turn into a crack - crevice - cave - arch - stack - stump by forcing air an water through the crack.
- weathering (freeze-thaw) weaken the top of the arch collapsing under the pressure
47
What processes of erosion does the formarion of stacks require
- Hydralic action
- quarrying
- abrasion
48
What is oxidation and reducitomn in terms of chemical weathering
- The addition or removal of oxygen.
-Oxidation results from oxygen dissolved in water and effect rocks with a high iron content.
- Reduction happens in waterlogged conditions.
49
Real life example of rock fall
- Svalbard
50
Real life example of rock slides
- Limestone cliffs of the gower in south wales
51
Real life example of rock toppling
- Giants causway in country Antrim, in Northern Ireland
52
Real life example of slips
- Sandy boulder clay deposits in North Northfolk
Issy As-Level geography
flashcards
Decks in class (13)
# Cards
-
Topic 1.1.1 operation of the coast system17
-
Topic 1.1.2 temporal variations and their influence on the coastline32
-
Topic 1.1.4 Factors affecting coastal processes and landforms40
-
JCL - Plate margins8
-
Volcano JCL - E15 Case study28
-
Earthquake JCL - Case study48
-
1.1.3 - landforms and landscape systems20
-
1.1.552
-
1.1.647
-
1.1.755
-
1.1.823
-
JCL Volcanoes2
-
Geography fieldwork study61
