Geography Grade 9
Geomorphology
Weathering
Weathering is the process of breaking down and disintegration of rock
Mechanical (Physical) weathering
Ice-shattering
Rain into cracks/holes in rocks
Frozen water expands forcing cracks to widen
Eventually breaks rock apart
Granular disintegration
Expansion and contraction
Rocks expand when heated and contract when cooled
Causes tiny fractures within the rock + small grains of rock to break off
Exfoliation
Peeling off of layers
Occurs in hot dry climates
Chemical weathering
(High temp and moisture in air make chemical weathering quicker)
Carbonation
Acid rainwater dissolves the rock
Limestone caves are made when acidic groundwater seeps through
limestone rock
Oxidation
Oxygen mixes with minerals (Ions) in rock to form oxides
If rock contains iron it becomes red in color
Biological weathering
Animals and Plants wear away rocks
Weeds grow through cracks
Animals/humans chip the rocks when walking
Impact of humans on weathering
, Add to mechanical when we change the surface of the ground
Pollution adds to chemical
Biological weathering just by walking
By removing vegetation humans decrease chemical and biological
Fossil fuels dissolve in water = acid rain
Erosion and Deposition
Erosion is the removal and movement of weathered material
Deposition is the laying down of eroded material
River Terms
Source Start of river
Tributaries smaller rivers flowing into a bigger river
Confluence. Point where 2 rivers meet
Load (sediment)Solid material that has been or is being eroded, transported
or deposited
Mouth. End of river (normally ocean)
Methods of Transport
Traction rolling large stones and boulders along the bottom of the
channel
Saltation lifting and dropping of stones
Suspension carrying sand, mud and silt
Solution carrying minerals (dissolved fine particles)
Fluvial Cycle
Geomorphology
Weathering
Weathering is the process of breaking down and disintegration of rock
Mechanical (Physical) weathering
Ice-shattering
Rain into cracks/holes in rocks
Frozen water expands forcing cracks to widen
Eventually breaks rock apart
Granular disintegration
Expansion and contraction
Rocks expand when heated and contract when cooled
Causes tiny fractures within the rock + small grains of rock to break off
Exfoliation
Peeling off of layers
Occurs in hot dry climates
Chemical weathering
(High temp and moisture in air make chemical weathering quicker)
Carbonation
Acid rainwater dissolves the rock
Limestone caves are made when acidic groundwater seeps through
limestone rock
Oxidation
Oxygen mixes with minerals (Ions) in rock to form oxides
If rock contains iron it becomes red in color
Biological weathering
Animals and Plants wear away rocks
Weeds grow through cracks
Animals/humans chip the rocks when walking
Impact of humans on weathering
, Add to mechanical when we change the surface of the ground
Pollution adds to chemical
Biological weathering just by walking
By removing vegetation humans decrease chemical and biological
Fossil fuels dissolve in water = acid rain
Erosion and Deposition
Erosion is the removal and movement of weathered material
Deposition is the laying down of eroded material
River Terms
Source Start of river
Tributaries smaller rivers flowing into a bigger river
Confluence. Point where 2 rivers meet
Load (sediment)Solid material that has been or is being eroded, transported
or deposited
Mouth. End of river (normally ocean)
Methods of Transport
Traction rolling large stones and boulders along the bottom of the
channel
Saltation lifting and dropping of stones
Suspension carrying sand, mud and silt
Solution carrying minerals (dissolved fine particles)
Fluvial Cycle
