Weathering and erosion slowly alter landscapes over time through physical and chemical processes. Weathering breaks rocks into smaller pieces of sediment through mechanical and chemical breakdown without changing the rock's composition. Erosion then transports this weathered material like sediment, forming new landforms as it is deposited by forces such as wind, water, ice or gravity. These gradual changes to the earth's surface through weathering and erosion impact how humans interact with their environment.
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Geography Chapter 2.4 external forces
1.
2. Wind, heat, cold, glaciers, rivers, and
floods alter the surface of the earth.
The results of weathering and erosion
change the way humans interact with the
environment.
3. Weathering is the physical and chemical
processes that change the characteristics of
rock on or near the earth’s surface
Can change landscapes over time and create
soil for plant life
- Occurs slowly over MANY years, even centuries
4. The image shows
weathering of
sandstone and shale.
The steep cliffs are
made up of
weathering resistant
sandstone, while the
slope at the base of
the cliff is composed
of rock units
containing a larger
abundance of shale.
5. The surface
pattern on this
pedestal rock is
honeycomb
weathering,
caused by salt
crystallization.
This example is at
Yehliu, Taiwan.
6. • A maze of hoodoos in Bryce Canyon National
Park in southern Utah in the early morning. This
photo was taken on a sunny day in May 2002.
7. Weathering creates smaller and smaller
pieces of rock called sediment.
-Sediment can be identified as fine particles of rock
such as mud, sand, silt, etc.
8.
9. Processes that break
rock into smaller
pieces
- Does not change the
composition of the rock –
ONLY ITS SIZE!
- Many factors can
contribute to mechanical
weathering including;
water, ice, wind, plants,
animals and even humans!
10.
11.
12.
13. Occurs when rock is actually changed into a
new substance due to the interactions of the
elements in the air, water or minerals.
- Climates that are warm and moist will produce more
chemical weathering than cool dry areas.
14.
15.
16.
17. Sea caves form from
carbonation, a type of
chemical weathering.
18. Occurs when weathered material is moved by
the action of wind, water, ice, or gravity.
Ex. Water carrying topsoil from a hill into a river will
cause the river to narrow.
19.
20. 1) when water flows in a stream or river,
picks up loose material and moves it
downstream
21. 2) abrasion, grinding away of rock by
transported particles
22. 3) water dissolves chemical elements in the
rock (changes composition of rock)
23. When a river enters an ocean, the sediment
is deposited in a fan-like landform
25. Waves on a coastline may also change the
land
Waves can reduce or increase beaches
Sediment from waves may build up sand bars
or islands
26.
27.
28. Double trouble
Dana Goegelman looks over the
damage and erosion to the beach
beside her parents hotel in
Indiatlantic, on Tuesday, Sept. 28,
2004. The Casablanca Inn was
damaged by Hurricane Frances
and then later lost much of its
beach and walkway to erosion
when Hurricane Jeanne pounded
the Florida coast on Sunday. (AP/
Dave Martin / September 28,
2004)
29. loess (LOH•uhs)
windblown silt and clay sediment that produce very
fertile soil
silt – fine sand carried by moving water
46. Different kinds of moraines on and near Gornergletscher, Valais,
Switzerland: 1 - lateral moraines, 2 - middle moraines, 3 - terminal
moraine (this moraine was deposited during the Little Ice age by the
small cirque glacier of which two remnants remain, above and above
left of the letter "3".