GEOGRAPHY YEAR 10

Weathering and what type of process is it?

• Happens outside the water when rock is broken down by natural processes from the Earth

• (ie, rainfall, temperature or chemical reactions)

• in situ (at one place)

• and its a sub ariel process

erosion and what type of process?

• when rock is broken down by the force of water

• its a marine process. This continuos action helps shape coast lines

name four different types of erosion

• attrition, -

• abrasion,

• solution

• and hydraulicaction

attrition

• material (mainly rocks) carried by waves gets rounder and smoother

• this is because it collides with other rocks/ materials causing sharp edges to get knoched off

abrasion

• waves throw stones and rocks at cliffs

• rocks scrape against the cliff wearing it away

• rocks keep rubbing against cliff over time until it’s loose therefore eventually eroding

solution

• chemical reaction its when salt water reacts with different rocks

• chemical reaction between them causes rocks to slowly erode and disslove

hydraulic action

• waves crash against cliffs at high forces

• over time waves force air pockets into the cracks in the rocks

• the air then expands causing cracks to widen and loosen

where would erosion be higher

• large fetch (so long fetch allows waves to grow in height and strength, making them more destructive to the coastline because they generate more force)

• softer rock (really weak so it erodes wuite quickly)

• area with a lot of destructive waves (because strong the backwashes leads to erosion)

• rocks with more gaps (hydraulic action)

name 3 main different types of weathering

• freeze thaw

• chemical

• biological

what is mechanical weathering give examples

• Mechanical weathering (also called physical weathering)

• is the breakdown of rocks into smaller pieces without any chemical change.

• The rock’s minerals stay the same, only the size and shape change. examples are feeze thaw and exfoliation

freeze thaw weathering when does it occus and how

• occurs when rocks are porous (contain holes) or are permable (allows water to pass through)

• water first enters cracks in the rock

• temperature drops below 0 degrees celcius and the water turns into ice. It expands by freezing and begins to push the rock apart

• then when temperature rises the ice in the crack will melt so the water makes it way deeper into the crack

• process repeats until rock splits entirely

biological weathering + how could it be chemical

• weathering cause by plants and animals

• animals might burrow into cracks and plants might grow their roots within

• so as burrow or roots grows the crack becomes larger causing small pieces of rocks to break away

• (or lichens and mosses release chemicals that dissolve the rock)

chemical weathering

• rainwater and sea waters are weak acids

• so because of them coastlines made of limestone or chalk dissolves in water over time

• (another examples is carbonation its when weak carbonic acids attack rocks)

exfoliation

• common in hot climates aka onion skin weathering

• surface layers of the rock are heated so it expands during day

• at night the outer layer cools down and contracts more than rest of the rock

• cracks will form and rocks start to peel away like an onion

what is meant by permability and what are impermable rocks

• the permability of a rockk defines hiw vulnerable a rock is to erosion

• Impermable rocks are less vulnerable as water is not absobed into the rock

what does igneous and sedimentry mean

• igneous is the strongest rock therefore it erodes slowly

• sedimentry is the weakest rock so it erodes really quickly

what is mass movement

• the shifting of loose material downa slope

how does mass movement happen and what does it cause

• Weathering weakens coastal rocks.

• Gravity causes them to collapse (mass movement).

• Material falls to the sea and is eroded by waves.

how are waves created 

• Waves are caused when the wind blows over the sea transferring some of its energy. 

• Friction with the sea water causes ripples to form and these develop into waves as they reach the coast.

what does a fetch do and what is it

• a fetch determines the height if a wave

• a fetch is how far and how long wind has been blowing over the sea

what is long shore drift and how does it work

• long shore drift is the movement along the shore by wave action. It haooens when waves aproach the beack at an angle due to prevailing winds

• the swash (waves moving up the beach) carries material up along the coast line

• the backswash (waves moving back down the beach) carries material back down the beach at right angle 

• once the waves loose energy material is deposited further down the bay to form a beach

what type of weathering caused this

• mechanical weathering (freeze thaw) this is possible due to low temperature

what type of weathering caused this and why

• chemical weather the holes seen are formed due to rain (which is slightly acidic) -

• so when the acid reacts with certain minerals dissolved the parts of rocks 

• so over a long period pits and holes such as the one you see are formed

what type of weathering is seen

• biological weathering 

• the trees is seen growing in the cracks of the rock which will eventually erode it

3 main things waves do

• they wear away or erode coasts

• carry and transport eroded material

• they drop or deposite it in sheltered areas when they loose energy 

• so waves shape the coastline by eroding transporting and depositing material

what’s traction, saltation and suspension

• traction is when rocks roll aong the sea bed

• saltation is when rocks bounce along the sea bed

• suspension is when rocks are carried by  the water

7 features of destructive waves

• height- is high (more than 1m)

• length- short

• Frequency - more than ten a minute

• energy- high

• beach gradient- steep

• main process- erosion

• strong back wash but weakerswash

7 features of constructive waves

• height- is low (less than 1m)

• length- long

• Frequency - fewer than ten a minute

• energy- low

• beach gradient- flat

• main process- depostion

• strong swash but weaker back wash