Weathering is the wearing away or slow breaking apart of rock into smaller pieces.
Plant
roots, ice, wind, and water are all causes of weathering.
The crushed rocks and rubble are called sediments,
– very slow process
– creates soil
– softer rock weathers faster
– weathering is fastest in hot and wet climates
Freeze thaw weathering
Onion skin weathering
Biological weathering
Chemical weathering
The hardness and composition of rocks, amount of rainfall, temperature and level of
pollution may affect how fast the rocks breakdown.
A landform is a feature on Earth's surface that is part of the terrain. Mountains, hills,
plateaus, and plains are the four major types of landforms.
Process of forming landforms.
Erosion Transportation Deposition
Erosion is the movement of sediment from one place to another.
Deposition
Sediment is created through the process of weathering, carried away through the process
of erosion, and then dropped in a new location through the process of deposition. When
wind and water slow down, they drop the sediments they are carrying.
• Water is the strongest agent of deposition.
• Wind is the weakest agent of deposition.
Formation of a V-shaped valley
A v-shaped valley is formed when the river moves through the upper course and it cuts
downwards.
Features of a river
Source- the start of the river
Drainage basin -an area of land drained
by a river and its tributaries
Tributary - a small stream that joins on
to a larger river
Floodplain - is the low-lying land
adjacent to a river and is prone to
flooding when the water level rises.
Meander - a bend in a river channel
Confluence - where a tributary joins a
larger river/ 2 or more streams or river
channels meet
Mouth - where a river enters the sea
Estuary - a partially enclosed, coastal
water body where freshwater from rivers
and streams mixes with salt water from
the ocean
Delta - Wetlands at the end of rivers
where the land flattens and the water
flow spreads into a fan shape
Waterfalls
Formation of a waterfall:
Coasts
Coastal landforms: - Landforms which occur on coasts include headlands, bays, caves,
arches, stacks and stumps.
Changes of the coast depend on the types of rocks that are in different areas. Harder
rock, like limestone and sandstone, erodes slowly. Softer rock, like clay, erodes more
quickly.
Beaches - Beaches are large deposits of sand and shingle (fragments such as pebbles
and gravel) and are caused by waves hitting a coastline.
Spits - A spit is a long narrow strip of land which is formed due to deposition
Changes in sea level:
Sea levels change on a daily basis due to tides.
However, earth’s sea levels are also generally rising due to global warming. The increase
in the earth’s average temperature is causing the polar ice caps to melt, causing sea
levels to rise.
This rise in sea levels can increase erosion and can cause area to permanently flood.
This affects coastal areas but can also affect low lying countries, such as the Maldives
and cities such as New York, Shanghai and London, which will be forced to spend
billions on flood defences.
Problems caused by coastal erosion
Loss of habitat
Loss of beach / tourism
Loss of landscape quality
Loss of agriculture
Loss of buildings
Loss of infrastructure such as roads, train tracks and power lines
Reduce tolerance to face natural hazards
Increased flooding
Decreased water quality
Ways to reduce the effects of coastal erosion
(Rip-rap)
Glaciers
Glaciers are slow moving rivers of ice which are made from compacted snow.
In the winter months, precipitation falls as snow. Over many years, layer upon
layer of snow compacted and turned to ice. As this ice grew thicker and thicker,
it began to spread out. Gravity was pulling it down causing the glaciers to
"move," or advance.
Processes involved with glaciers:
1) Freeze-thaw weathering – when rock is cracked by the freezing and thawing
of ice.
2) Plucking is caused when sediments are picked up by a glacier. They freeze
to the bottom of the glacier and are carried away by the flowing ice.
3) Abrasion occurs when glaciers scrape over the Earth's surface. The ice sheet
acts like sandpaper. The rocks and sediment frozen in the ice grind away as
the glacier moves.
The scraping causes the sides of the valley to be eroded. Glaciers carve out
a U-shaped valley.
Moraine is sediment deposited by a glacier.
Corrie
Snow collects in hollows and turns to glacial ice and moves downwards under
the force of gravity Rocks are plucked out and the hollow is widened to
become a corrie. A corrie is a deep, rounded hollow with a steep head or back
wall. They are usually ‘armchair’ shaped depressions on a hillside with a steep
back wall, often containing a lake (tarn).
Corrie features
Corries produce the following erosional features:
arêtes - this is a narrow ridge of land that is created when two corries
erode back towards each other
pyramidal peak - if three or more corries erode back towards each
other, at the top of a mountain a pointed peak is left behind
U-shaped valley: Steep sided valleys which form when glaciers erode V
shaped valleys.
Hanging valleys: Steep drop offs in U shaped valleys which form when the
sides of V shaped valleys erode and they often create waterfalls.
Truncated Spurs: River valleys have ‘Interlocking spurs’ like the teeth in a zip
that overlap. However, a glacier removes them and makes the valley straight.
Ribbon Lakes: Long, narrow lakes which fill U shaped valleys after glaciers
have melted.
Erratics: boulders left behind in areas with totally different rocks by a glacier
once it has melted.
