The UK’s Evolving Physical Landscape - Topic 4 Flashcards
Define Igneous Rock
Igneous rocks are formed by magma from the molten interior of the Earth. When magma erupts it cools to form volcanic landforms. Igneous rocks are formed on the Earth’s surface and underground. They are very resistant rocks.
Define Metamorphic Rock
Metamorphic rocks begin as igneous or sedimentary rocks but they are later altered by heat or pressure which causes them to change into another type of rock. They are very resistant rocks.
Define Sedimentary Rocks
Sedimentary rocks are formed from sediments that have settled at the bottom of the sea and they have been compressed over millions of years. Small particles of rock transported by water, ice and wind. These rocks are generally resistant.
Define Weathering
The physical, chemical, biological breakdown of solid rock by the action of the weather or plants.
Define Physical Weathering
Rain gets into cracks and freezes. The force is strong enough to break the rock (freeze thaw).
The Sun causes rocks to warm up and expand (onion skin).
Define Chemical Weathering
There are chemicals in the air and causes rain to become acidic. Acid rain goes into cracks in the rocks like limestone which causes the cracks to become bigger and wears away the weak rock.
Define Biological Weathering
Burrowing animals and plants attacking rocks and weakening their structures. Plant roots can grow in cracks making them bigger. Eventually, pieces of rock fall away.
Formation of Scree
The exposed surface is affected by freeze thaw weathering because water enters the cracks and it freezes and expands. As the water expands, the cracks expand as well. This process is repeated and material and pieces of rock fall and start to form scree. This is very unstable and it may lead to a landslide.
Landscape formed by chemical weathering limestone pavement (Yorkshire Dales)
Limestone pavement is a gentle sloping expanse of bare limestone. It consists of large blocks of limestone that are separated by deep eroded grykes (large cracks).
Acidic rain falls onto the limestone and reacts with the limestone caus8ng cracks to form. The chemical weathering makes the cracks widen and deepen. This leaves blocks of limestone which are called clints. These grykes can then expand causing/creating caves.
Define Erosion
Erosion is the wearing away of the land and transportation away of material.
Define Headland
A piece of land jutting out into the sea.
Define Stack
A geological landform consisting of a steep and often vertical column or columns of rock in the sea near a coast, formed by wave erosion. They are formed by the sea attacking the weak rock in a headland and cracks start to form. The cracks in the rock that start to grow and form a cave. Two caves form either side of the rock due to erosion from the sea/waves and an arch is formed (eg. Durdle Door). As nothing is able to support the arch, it collapses leaving a stack.
Define Stump
Overtime, a stack gets eroded and becomes smaller and it has then become a stump.
Define Bay
A broad coastal inlet often with a beach.
Define Discordant Coastline
Hard and soft rock that are perpendicular to the sea.
Define Concordant Coastline
Rocks are parallel to the sea. (Lulworth Cove)
Define Hydraulic Action
The power of the waves putting pressure on the cracks in the cliff.
Define Abrasion
Rocks in the sea scrape along a cliff like sand paper or smash into the cliff.
Define Solution
Where there is a chemical reaction between the water and rock. The rock dissolves.
Define Attrition
Rocks hit each other in the sea and get smaller.
Define Fetch
The distance over which the wind has blown.
Define Wave Cut Platform
The narrow flat area often found at the base of a sea cliff or along the shoreline of a lake, bay or sea that was created by the erosion of waves.
Define Prevailing Wind
The main direction that the wind comes from.
Define Permeable
Allows water to drain through the rock.
Define Impermeable
Doesn’t allow water to drain through the rock.
Define Hard Engineering
Building physical structures to deal with the natural hazards such as sea walls to stop waves.
Define Soft Engineering
Involves adapting to natural hazards and working with nature to limit damage.
Define Longshore Drift
Waves transport material along the coastline.
Define Deposition
The dropping of material.
Define Spit
A spit is an extended stretch of beach material that projects out to sea and it joined to the mainland at one end. It is caused by waves depositing material.
Define Bar
A bar is similar to a spit. It is a ridge of sand or shingle which form across the mouth of a river or the entrance to a bay or harbour.
Define Destructive Waves
Waves that are steeply breaking and are mainly responsible for coastal erosion. Their backwash is much stronger than their swash.
Define Constructive Waves
These waves are gently breaking with a much stronger swash than backwash. They are mainly responsible for coastal deposition.
Rivers and Drainage Basins
Sub topic
Define Source
The start of a river.
Define Tributary
When a smaller river joins the main river channel.
Define Drainage Basin
Water that falls in a certain area around the river, gets drained into the river. A drainage basin works by: -Inputs of water -Flows through it -Stored areas in it -Outputs out of the drainage basin
Define Watershed
A boundary of hills surrounding the drainage basin.
Define Transpiration
Plants absorb water through the roots and then give off water vapour through pores in their leaves.
Define Precipitation
Any type of water that forms in the earth’s atmosphere and then drops onto the surface of the earth. Precipitation falls to the ground as snow and rain.
Define Interception
When water gets stopped from falling to the ground by vegetation.
Define Infiltration
Movement (transfer) of water into the soil from the surface.
Define Surface Runoff
Water that flows over the land to the sea.
Define Throughflow
The water moving (slowly than surface runoff) through the soil back the river.
Define Percolation
Some water moves deeper into the ground and is slowly transferred back to the river or sea.
Define Groundwater Flow
Water flowing through rocks underground to the sea.
Define Evaporation
Water changes state from a liquid to a gas.
Define The Long Profile
How the river changes in height along its courses.
Define Traction (erosion of a river)
Large stones are dragged along.
Define Solution (erosion of a river)
Dissolved chemicals are carried along, invisible to the eye.
Define Suspension (erosion of a river)
Tiny particles of sediment are carried in the river’s current.
Define Saltation (erosion of a river)
Smaller stones or pebbles are picked up and then dropped again. This results in a ‘skipping’ motion.
Define Deposition (erosion of a river)
Dropping of the river’s load where it does not have energy.
Formation of a Waterfall
A waterfall is formed when a river flows over the edge of different bands of rock. Overtime, the water causes the soft rock to erode. The energy form the water causes the ground at the bottom of the waterfall to erode, creating a plunge pool and an undercut is created because the spray of the waterfall eroded the soft rock. The soft rock continues be eroded rapidly which creates an overhang. The overhang is just hard rock which is heavy and isn’t supported by anything so it collapses into the plunge pool. This keeps happening and the waterfall moves further and further back overtime. A gorge is then formed because of the waterfall causing the rock to continue to erode backwards.
Define Thalweg
The fastest part of the river.
Define Flood Plain
A flat area of land that can get flooded.
Define Alluvium
The sands and clays brought down by the river from upstream and settle over the flood plain and form layers.
