Rivers and Weathering - Video Notes

Vocabulary-style flashcards covering rivers, river processes and landforms, weathering, and human impacts as described in the notes.

River

A large natural stream of water flowing in a channel downstream due to gravity.

Source

The starting point where a river begins.

Mouth

The place where a river enters an ocean, lake, or sea.

Tributary

A smaller river that flows into a larger river.

Confluence

The point where two rivers meet.

Watershed

An area of high land that separates drainage basins; marks the edge of a basin.

Drainage basin

An area of land drained by a river and its tributaries.

River basin

The land area drained by a river and its tributaries.

Longitudinal profile

The elevation profile of a river from source to mouth.

Upper course

The section near the source with a steep gradient and rapid flow involving vertical erosion.

Middle course

The middle section with a moderate gradient and more lateral erosion.

Lower course

The final section with a gentle gradient where deposition increases.

Gradient

The change in elevation along a river; can be steep or gentle.

Rapid

A fast-flowing stretch of a river, often in a steep or rough bed.

Meander

A broad, winding bend in a river's course.

Waterfall

A point where a river drops vertically due to differing rock hardness.

Rapids

Sections of fast, turbulent water over irregularities in the bed.

Ox-bow lake

A crescent-shaped lake formed when a meander is cut off from the river.

Gorge

A deep, narrow valley with very steep sides carved by erosion.

Levee

An elevated bank along a river to prevent flooding.

Canyon

A deep valley with steep sides formed by river erosion.

Delta

A landform at a river mouth formed from deposited sediment.

Traction

Movement where large rocks are pushed or rolled along the river bed.

Saltation

Bouncing movement of medium-sized stones along the river bed.

Suspension

Fine particles carried within the water flow.

Solution

Material dissolved in the water.

Erosion

The wearing away of rock by natural agents such as water.

Weathering

Breakdown of rock by weathering processes (physical, chemical, biological).

Deposition

Dropping of sediment when the river loses energy.

Freeze-thaw

Physical weathering where water in cracks freezes and expands, splitting rock.

Exfoliation

Peeling of outer rock layers due to heating and cooling cycles.

Oxidation

Chemical weathering where minerals react with oxygen, often reddening iron-rich rocks.

Hydrolysis

Chemical weathering where water reacts with silicates to form clays.

Carbonation

Chemical weathering where carbonic acid from CO2 dissolves calcite (CaCO3) in limestone.

Carbonic acid

The acid formed when CO2 dissolves in water.

Limestone

Rock rich in calcium carbonate (CaCO3) that undergoes carbonation.

Calcium carbonate (CaCO3)

Mineral in limestone; dissolves during carbonation.

Calcium bicarbonate (Ca(HCO3)2

Soluble product formed during carbonation that dissolves in water.

Plungpool

The deep pool at the base of a waterfall formed by erosion.

Undercutting

Erosion that wears away under softer rock, creating an overhang.

Overhang

Hard rock that juts out after undercutting leaves unsupported rock.

Stalactite

Mineral formations hanging from a cave ceiling formed by deposition.

Stalagmite

Mineral formations rising from a cave floor formed by dripping minerals.

Underground cave

Caves formed when carbonic acid dissolves rock underground.

Lichen

A symbiotic organism that grows on rocks, producing acids that chemically weather rock.

Biological weathering

Weathering caused by living organisms, including plants and animals.

Deforestation

Removal of forests, exposing soil and rocks to weathering.

Dams

Structures that create reservoirs; water behind dams can erode soil and rock.

Farming chemicals

Agricultural chemicals added to soil influencing weathering processes.

Burrowing animals

Worms, moles, and other animals that disturb soil, aiding weathering.

Fires

Heat from fires can alter soil and rock, promoting weathering.

Underground tunnels

Subterranean passages that can weaken rocks.

Human settlements

Development that exposes soil and rocks to weathering.

Acid rain

Rain that contains acids from air pollution and corrodes rocks.