1. Surface Processes on Earth Weathering, Erosion & Freshwater

2. Weathering and Erosion
Weathering is the process of breaking down rocks at or near the Earth’s surface.
Erosion is the movement of sediments from one place to another.

3. Weathering
Mechanical
Chemical

4. Mechanical Weathering
Does NOT change the rock
CHEMICALLY
Natural processes just eat away
at (Erode) the surface

5. Mechanical Weathering
FROST/ICE WEDGING: repeated thawing and freezing of water in cracks of rocks
UPLIFTING: when layers of rock above are removed, the release of PRESSURE allows the rock to expands and cracks
Plant growth into cracks can split open rocks
EXFOLIATION: the action of EXFOLIATION allows outer rock layers to be striped away

6. Chemical Weathering
Occur when CHEMICAL REACTIONS take place within the rock
Eroded sediments are different chemically
Erosion Increases with SURFACE AREA
Water, oxygen, carbon dioxide and acids can cause chemical weathering

7. Chemical Weathering Hydrolysis = water. Occurs in Silicate Minerals
Oxidation = oxygen. Occurs in Iron Minerals = RUST
Carbon dioxide. Combines with water to form a
weak CARBONIC acid
Acid Rain. Released by human activities that make pollution.

8. Rate of Weathering
Water-Soluble minerals weather easily (Like salt melts into salt water)
Different layers weather at different rates

9. Other Factors More surface area = more weathering
Topography (slopes, hills, etc) allows gravity push sediments downhill faster than on flat surfaces

10. Erosion
Transportation of Sediment
Water
Wind
Glaciers

11. Soils Or as some call it.. Dirt

12. Soils Soil is made of Soil Texture depends on particle SIZE
Rock particles and minerals (sand, silt, clay)
Humus is organic and provides PLANTS with air and water
Soil Texture depends on particle SIZE

13. Soil Horizons The layers of soil are called the soil horizon
TOP SOIL – Layer A: contains NUTRIENTS and minerals and is very dark
SUB-SOIL- Layer B: high in clay and is usually red or yellow in color
Layer C: Partially weather rock

14. Life in Soil
Decomposers (such as fungi and bacteria) break down ORGANIC MATERIAL
Animals mix SOIL LAYERS and allow air and water to pass through it.
Humus = Plants produce litter and then decay which returns nutrients to the soil.

15. Soil in the U.S.
Polar (Alaska) – good drainage, no horizons, permafrost
Temperate (Eastern and Central U.S.) – vary greatly
Grassland – fertile
Forest – less fertile
Desert (Western U.S.) – high in salts and little organic/living material
Tropical – can become infertile due to high rainfall

16. Soil Damage Loss of TOP SOIL Due to erosion Desertification
Climate Change, Overgrazing, Cutting down FORESTS

17. Conservation Contour plowing CONSERVATION plowing
Fallow (allowing fields to rest)
CROP rotation

18. Karst Topography Differential erosion causes KARST TOPOGRAPHY.
Groundwater contains some ACID usually CARBONIC ACID
Acid gets there when carbon dioxide combines with water
Differential erosion causes KARST TOPOGRAPHY.
Acid dissolves some types of minerals
Calcites
Limestone
Acid leaves others
Quartz
Sandstones
Igneous rocks

19. Features of Karst Caves Sinkholes Stalactites – from above
Stalagmites – from below
Disappearing rivers

20. Karst Topography

22. Caves

24. Sink Holes

25. Stalactites
They hold TIGHT to the ceiling

26. Stalagmites
They MIGHT have fallen

27. Disappearing Rivers

28. Mass Movement by Gravity
The downward movement of loose sediment and weathered rock.
Slide: moves as a block
Flow: particles mix together
Fall: falling freely

29. Slow, Steady, Downhill flow of sediment
Creep
Slow, Steady, Downhill flow of sediment

30. Mass of sediment falls down
Slump
Mass of sediment falls down

31. swiftly moving mixture of mud and water
Mudflow
swiftly moving mixture of mud and water

32. downhill movement of saturated topsoil
Landslide
downhill movement of saturated topsoil

33. Landslides of snow (deep snow)
Avalanche
Landslides of snow (deep snow)

34. Mass Movement Caused by Wind
Mass movement from wind includes
Dust Storms
Dunes Formation

35. Mass Movement by Glaciers
A glacier is a large moving mass of ice

36. The Water Cycle

37. Runoff Water moving along the surface will carry sediments.
If surface is POROUS, then water can flow into the ground.
Plants slow erosion and allows more water into the ground
Light rains can allow more water into the ground
Soil types affect absorption

38. Run Off & Porosity

39. Watershed
All the land that drains into a stream or river system is called the watershed.
Suspension: particles carried in water
Bed Load: particles pushed along by water in a stream

40. Streams Stream channel: the pathway carved by a stream
Stream banks: the ground bordering the stream on either side
Floods occur when streams or rivers rise over their banks.
Flood plain: the broad flat area on either side of the stream banks.
Meander: the bend and curves in a stream

41. Streams

43. Lakes and Freshwater Wetlands
Lakes are depressions in the landscape that collect and hold water.
Eutrophication: the process by which lakes absorb nutrients from the soil around them.
Wetlands are land areas that are covered by water for part of the year.
Bogs
Marshes
Swamps

45. Groundwater and Infiltration
Infiltration is when water on the surface flows into the ground
An aquifer is the area of ground water flow through permeable rock

46. Groundwater

47. Groundwater
Zone of Saturation – the depth to which ground water completely fills all the pores in the material.
Upper boundary is the Water Table
Permeability – how easily water passes through
Zone of Aeration – is the area above the water table

49. Groundwater Systems
Springs - Natural discharges of ground water where ground water is blocked by AQUICLUDES (Clay and Shale)
Hot springs usually form near residual igneous activity
Geysers are explosive hot springs that erupt at regular intervals.

51. Wells
Wells are holes that are drilled or dug into the ground to reach the aquifer
Drawdown – the difference between the water table level and the water level in the pumped well
Recharge – the water filtering into the well from the ground water
Artesian well – a well in a CONFINED aquifer.