1. Earth’s Changing Surface
Chapter 7

2. Weather and Erosion are major forces that shape the Earth's surface.
Example: The Grand Canyon was formed by the Colorado River running through it.
Weather and Erosion are major forces that shape the Earth's surface.

3. Surface processes
the process of erosion and weathering affecting the geosphere
a process caused by nature rather than by the deliberate act of human beings

4. What is weathering?
Weathering = The breaking down of rocks into smaller pieces.
1. Physical
2. Chemical

5. So what is Erosion?
Erosion = The movement of weathered rock by wind, rain, glaciers, and gravity.

7. Types of Weathering
Mechanical / Physical
Chemical
Rocks are physically broken into smaller pieces (larger pieces become smaller pieces of the same rock
Rock is chemically changed like rusting or dissolving away

8. 5 Ways of Mechanical Weathering:
1. Release of Pressure 2. Freezing & Thawing 3. Animal Actions 4. Plant Growth 5. Abrasion

9. Release of Pressure
As the surface of a rock is eroded, the rock begins to release pressure
Causes top layers of the rock to crack and flake off
Release of pressure causes rock to crack like an egg shell

10. Freezing and Thawing
When water in the cracks of rocks freezes it expands
This causes the crack to get bigger
The ice melts and refreezes over and over again
This action breaks the rock apart

11. Animal Actions
Animals dig (burrow) through the ground to make their homes
This loosens the soil and breaks rocks apart

12. Plant Growth Plant roots can grow into cracks in the rock
When the plant grows the roots thicken widening the crack in the rock

13. Abrasion
Sand and other rock particles in the wind, water, or ice can wear away rock surfaces
Just like sandblasting or sandpaper on wood

15. = The process that breaks down the surface of rock by chemical changes
Chemical Weathering
= The process that breaks down the surface of rock by chemical changes

16. 5 Causes of Chemical Weathering
Water
Oxygen
Carbon Dioxide
Living Organisms
Acid Rain

17. Water Water dissolves rock
Water is the MOST important cause of chemical weathering

19. Oxygen Oxygen + Water + Iron = Rust
This chemical reaction is called Oxidation
Rocks will become crumbly, soft, and appear reddish-brown

20. Carbon Dioxide Carbon Dioxide (CO2) + water = Carbonic Acid
Carbonic Acid weathers softer rock like limestone and marble as it seeps into spaces in rock
Examples: sinkholes, caves

21. Living Organisms
The roots of plants make a weak acid that slowly dissolves rocks around the plant

22. Acid Rain Acid rain causes rocks to weather very rapidly
Pollution causes acid rain

23. Horizons = layers of soil which develop over time
A = Topsoil
B = Subsoil or larger rock particles
C = Regolith of weathered rock
D = solid rock

24. 7. 2 Earth’s Surface

25. Deposition particles of rock are laid down in layers
Heavier particles are dropped first and then covered by finer material
Layers of sediment build up over time

26. Drainage Basin
any area of land where precipitation collects and drains off into a body of water.

27. River Delta = a landform that forms from deposition of sediment
The sediment is carried by a river but does not have the energy/speed to carry it all away so is deposited at the mouth of the river
This occurs where a river enters a larger body of water and cannot carry away the sediment

28. Sinkhole
 is a depression in the ground that forms when the rock beneath the surface collapses

29. Longshore Current is an ocean current that moves parallel to shore
It is caused by large waves sweeping into the shoreline at an angle and pushing water down the length of the beach in 1 direction

30. Glacier Large area of ice on land
formed by the accumulation and compaction of snow on mountains or near the poles

31. a mass of rocks and sediment carried down and deposited by a glacier
Moraines
a mass of rocks and sediment carried down and deposited by a glacier

32. Plateau is an area of a land higher than surrounding area
consisting of relatively flat land that is raised significantly above the surrounding area
often with steep slopes

33. 7.3 Development of Features

34. Active Margin
Oceanic crust goes under the continental crust forming a trench (dip)
is found on the leading edge of the continent where it pushes into an oceanic plate
sites of tectonic activity like earthquakes and volcanoes

35. Passive Margin Begins at divergent plate boundaries
As the plates move apart oceanic crust is added  
Continental rifting creates new ocean basins
Page 431

36. Isostatic Equilibrium
Huge plates of crust and upper mantle (lithosphere) “float” on more dense, plastically flowing rocks of the asthenosphere
The balance is called isostatic equilibrium
Isostatic = restored with negative feedback
Equilibrium = forces in balance

37. Is the upward motion caused from convergent plates lifting large areas
Uplift
Is the upward motion caused from convergent plates lifting large areas

38. the sinking of the Earth's crust on a large scale
Subsidence
the sinking of the Earth's crust on a large scale