river landscape and processes Flashcards
What is abrasion?
A form of erosion where loose material, pebbles and sediment ‘sandpaper’ the walls and floors of a river, cliff or glacier.
What is attrition?
Rocks and pebbles continuously hit against each other, causing them to break into smaller rocks until they become sediment.
What is backshore?
The upper beach closest to the land, including any cliffs or sand dunes.
What is beach nourishment?
The addition of sand and sediment to an eroding beach by humans.
What is biological weathering?
Rocks are broken apart by growing vegetation and roots, microbes, or chemical reactions from animal faeces.
What is a concordant coast?
A coastline where bands of alternate geology run parallel to the coast.
What is corrasion?
A form of mechanical erosion where material and sediment in the sea is flung at the cliff-face.
What is chemical weathering?
The weak acid in rainwater dissolves chemical compounds in the rock.
What is a discordant coast?
A coastline where bands of alternate geology run perpendicular to the shore.
What is fetch?
The length of water over which the wind has travelled.
What is freeze thaw?
A form of physical sub-aerial weathering where water freezes in the cracks of a rock, expands and enlarges the crack.
What is geology?
The physical structure and arrangement of a rock.
What is a groyne?
A form of hard-engineering. Low-lying concrete or wooden walls, constructed perpendicular to the seafront.
What is hard management?
The use of concrete structures to reduce or halt the recession of a coastline.
What are highlands?
An area of land that is at a high elevation and tends to have a larger relief.
What is hydraulic action?
The pressure of compressed air forced into the cracks of a rock face causes the rock to weaken and break apart.
What is igneous rock?
Rock that has formed from volcanic activity, often cooled magma on the Earth’s surface.
What is impermeable rock?
A rock that does not allow water to pass through it.
What is longshore drift?
The transportation of sediment along a beach.
What are lowlands?
An area of land that has a small relief, so tends to be flat and at a low elevation.
What is mass movement?
A large, downhill movement of material usually from a cliff-face.
What is mechanical weathering?
The breakdown of rocks due to forces (such as freeze-thaw), not chemical reactions.
What is metamorphic rock?
Rock formed under intense pressure and heat, often close to tectonic plate boundaries.
What is permeable rock?
A rock that allows water to pass through it.
What is relief?
The difference in the height of land for a particular region.
What is rock armour?
Large rocks or concrete blocks, used as barricades to reduce marine erosion at the base of cliffs.
What is saltation?
A form of sediment transportation where smaller rocks/pebbles are pushed along the seabed by currents.
What is a salt marsh?
In sheltered bays or behind spits, salt and minerals will build up.
What is a sand dune?
A depositional landform, where sand and sediment build up around driftwood.
What is a sea wall?
A hard-management coastal defense. A concrete wall is built parallel to the sea front.
What is sedimentary rock?
Formed from the broken remains of sediment and other rocks that have compressed and cemented together.
What is soft management?
The use of natural materials and environmentally sustainable approaches to reduce coastal recession.
What is solution?
Slightly acidic water dissolves chemicals from a rock face (usually limestone).
What is suspension?
Small rocks that are light enough to float are carried in the water.
What is a spit?
A long depositional landform, formed from sand and shingle.
What is traction?
Large rocks and boulders are rolled along the bed of the river or sea.
