Physical Environment Flashcards
Igneous rock
Formed by:
Give 2 examples:
Characteristics:
A rock formed from hardened magma/lava from volcanic eruptions.
- Hard, dense, permeable
Metamorphic Rocks
Formed by:
Examples:
A rock changed by extreme heat or pressure. Comprised of layers.
Example: Slate.
Sedimentary rocks
Formed by:
Examples:
Formed by: particles that have been eroded, transported and deposited in layers. Can be remains of animals or plants.
Examples: chalk and limestone.
Four types of mass movement:
- Rock fall
- Soil creeping
- Slumping
- Slides
Three things impacting rate of coastal erosion
2 things worsening
1 reducing
- Climate change causing more extreme weather conditions - waves have more energy.
- Winter has more frequent waves due to storms
- Coastal defences - could REDUCE the rate of erosion.
FOUR types of river erosion
- Hydraulic action
- Abrasion
- Solution
- Attrition
What is Hydraulic Action
Sheer force of the water hitting the river bed and banks.
What is Abrasion
Carrying material hitting the bank and beds, eroding them.
What is Solution
What type of rocks are most affected ?
When the river water is acidic, dissolves some rocks and minerals in contact with the river. Limestone and chalk most affected.
What is Attrition
Sediment particles in the river collide with each other, they become rounder and smaller downstream.
Slumping caused by:
Soil creep is caused by:
Slumping - bottom of a valley side eroded by a river, materials slide downwards.
Soil creep - soil brought down by gravity, collecting at the bottom, river sweeps it away.
What is river discharge
The amount of water in a river at any given time.
3 Reasons for lag between peak rainfall and peak discharge
- soil absorbs the water - takes time to reach it.
- vegetation may intercept water - leading to surface run.
- Proportion of water directly hitting the river is small - takes time to travel to it.
Advantages of a Dam/ Reservoir
4 reasons
- Can be used to control water flow/ prevent flooding
- Can be used to produce energy through hydro-electric power.
- Can be used to provide drinking water/ irrigation
- Made of long-lasting concrete
Disadvantages of Dam/ Reservoir
4 reasons
- An eyesore, can put tourists off.
- Expensive to build and maintain
- sediment gets trapped, less deposited downstream - more erosion.
- reservoirs can silt up.
Types of weathering
- Bio chemical
- Biological
- Bio physical
- Chemical
- Freeze thaw
What is Biological weathering?
When living things break up the rock. eg when tree roots grow into the joints of a rock and break it apart.
What is Bio physical weathering?
A rock physically being forced apart by a tree root for example.
What is bio chemical weathering?
flora and Fauna can secrete acids which dissolve the rock. eg most plants produce humic acid when they decompose.
What is freeze thaw weathering?
When water freezes it expands which can cause cracking in the rock. This can happen in cycles.
What is Chemical weathering?
Dissolves rock by acid rain and breaks down the rock through chemical reactions.
Why are some areas more vulnerable to drought?
3 reasons
- Blocking anticyclones - area of high pressure that blocks other weather coming in - extends dry spell.
- Over-consumption of water for farming causing a deficit in the area.
- Climate change - causes high pressure - less rainfall.
- Deforestation. - less transpiration in the air.
