weathering, erosion and soils
DESCRIPTION
2013 NC PPT for Academic and Honors Earth ScienceTRANSCRIPT
Created by L. Zimmerman
3:00
Created by L. Zimmerman
Physical (AKA – Mechanical) –
Abrasion –
Frost Wedging –
Plants –
Exfoliation -
Chemical –
Carbonation –
Oxidation –
Hydrolysis–
=
the breaking of rock into smaller particles called sediment.
Types of WeatheringTypes of Weathering
Mechanical (physical)–causes a rock to crack or break into pieces without changing it chemically
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it
chemically
Abrasion –
Frost Wedging –
Plants –
Exfoliation -
Chemical –
Carbonation –
Oxidation –
Hydration –
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Physical Weathering
Abrasion sediments carried by streams and wind blown
sand cause particles to collide into each other and the surrounding rock.
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it
chemically
Abrasion – Bump & Grind (streams/wind) smooth rounded particlesFrost Wedging –
Plants –
Exfoliation -
Chemical –
Carbonation –
Oxidation –
Hydration –
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Physical WeatheringFrost wedging
water seeps into the cracks in a rock and freezes causing the ice to expand.
Created by L. Zimmerman
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it chemically
Abrasion – Bump & Grind (streams/wind)Smooth, rounded particles
Frost Wedging – water seeps into the cracks in a rock and freezes causing the ice to expand
Plants –
Exfoliation -
Chemical –
Carbonation –
Oxidation –
Hydrolysis–
Acid Rain -
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Physical Weathering
Plants Trees and shrubs can
grow through cracks in rocks.
Their roots wedge into crevices.
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it chemically
Abrasion – Bump & Grind (streams/wind)
Frost Wedging – water seeps into the cracks in a rock and freezes causing the ice to expand
Plants – roots wedge into rock and grow (expand)
Exfoliation -
Chemical –
Carbonation –
Oxidation –
Hydrolysis–
Acid Rain -
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Physical Weathering
Exfoliation –cycle of heating and cooling causes the rock to expand & contract so it breaks off in slabs or layers.
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it chemically
Abrasion – Bump & Grind (streams/wind)
Frost Wedging – water seeps into the cracks in a rock and freezes causing the ice to expand
Plants – roots wedge into rock and grow (expand)
Exfoliation – Freeze & Thaw causes rock to “peel”
Chemical –
Carbonation –
Oxidation –
Hydrolysis–
Acid Rain -
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Chemical – Any process that causes rocks to breakdown by chemical action and results in a change in the minerals (chemical composition).
Types of Weathering
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it
chemically
Abrasion –
Frost Wedging –
Plants –
Exfoliation -
Chemical – involves water + it changes the rocks chemical composition
Carbonation –
Oxidation –
Hydration –
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Chemical Weathering
Carbonation – carbon dioxide in the atmosphere dissolves in the droplets of water that make-up clouds.
This forms a weak carbonic acid.
Carbonic acid reacts with certain rocks and minerals which include: calcite, limestone, marble and chalk.
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it
chemically
Abrasion –
Frost Wedging –
Plants –
Exfoliation -
Chemical – involves water + it changes the rocks chemical composition
Carbonation – CO2 + H2O form weak acid that dissolves limestone
Oxidation –
Hydrolysis–
=the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Chemical Weathering
Oxidation - Water + Oxygen = Rust
Created by L. Zimmerman
Chemical Weathering
Hydrolysis
Created by L. Zimmerman
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it
chemically
Abrasion –
Frost Wedging –
Plants –
Exfoliation -
Chemical – involves water + it changes the rocks chemical composition
Carbonation – CO2 + H2O form weak acid that dissolves limestone
Oxidation – Rust
Hydration – Water dissolves mineral to clay
=
the breaking of rock into smaller particles called sediment.
Chemical Weathering
Acid Rain – Gases produced by humans can dissolve in the water droplets of a cloud to produce acid rain. These acids include:
H2SO4 – sulfuric acid
HNO3 – nitric acid
Cleopatra’s Cleopatra’s NeedleNeedle
Over 3,400 years old & made of limestone – Installed in London and NYC in 1880’s
Photo shows before and after and effects of acid rain and rates of weathering!
Physical (AKA – Mechanical) –causes a rock to crack or break into pieces without changing it
chemically
Abrasion –
Frost Wedging –
Plants –
Exfoliation -
Chemical – involves water + it changes the rocks chemical composition
Carbonation – CO2 + H2O form weak acid that dissolves limestoneOxidation – RustHydrolysis – Water dissolves mineral to clayAcid Rain – pollution combines with water vapor produces weak acid that dissolves rocks.
=
the breaking of rock into smaller particles called sediment.
Created by L. Zimmerman
Rates of Weathering
FAST SLOW
ClimateTemp & Temp & MoistureMoisture
Cold/Warm & DryCold/Warm & DryWarm & Wet = fast chemicalWarm & Wet = fast chemicalCold & Wet = fast physicalCold & Wet = fast physical
Rock TypeRock Type Igneous & MetamorphicSedimentary
Shale/siltstone – conglomerate - limestone
Sandstone Dolostone
Rates of Weathering
Climate is the major factor that affects the rate of weathering
Due to climate and different weathering processes, landscapes develop differently.
Arid Climate – angular,
sharp edges, little
vegetation
Rates of Weathering
Humid Climate – soft, rounded with
vegetation
Rates of Weathering
Created by L. Zimmerman
Rock Types – cause softer, less resistant rocks to wear away, leaving harder, more resistant rocks behind.
Limestone (A) is most resistant
Shale (B) is least resistant
Rates of Weathering
Created by L. Zimmerman
Looking Glass Falls near Ashville shows differential weathering.
Rates of Weathering
Created by L. Zimmerman
Rates of Weatheri
ngFAST SLOW
TIMETIME Underground/lesstimeUnderground/lesstimeAbove GroundAbove Ground
Particle Size Or Surface
Area
Large size or less surface area
Small size or more surface area
Rates of WeatheringParticle Size – As a rock breaks into smaller pieces, the surface area increases, and therefore the rate of weathering increases.
Products of Weathering
Solid Sediments
Colloids • very small solid particles and too light to settle in water.
Size by name and number
Products of Weathering
It may mean calcium and lime deposits on your shower or if you have a well, sulfur and rust stains in the sink.
Dissolved Minerals – cause the “hardness” in groundwater (and surface water).
Chemical Weathering
Carbonation – carbon dioxide in the atmosphere dissolves in the droplets of water that make-up clouds.
This forms a weak carbonic acid.
Carbonic acid reacts with certain rocks and minerals which include: calcite, limestone, marble and chalk.
Created by L. Zimmerman
Created by L. Zimmerman
Cave Details
Created by L. Zimmerman
Carlsbad Cavern, New Mexico
Rocks, Weathering, and Soil Formation
Click for Clip
Soil Formation Soil Profile Climate is one of the most
important factors in formation of SoilSoil.
Soil varies in composition, texture, structure, and color at different depths.
These differences help divide the soil into zones known as HorizonsHorizons.
A side view of these horizons create a soil PROFILEPROFILE.
Soil Composition O O Horizon: organic matter that has fallen on
the ground and is decaying A A Horizon: topsoil (aka humus). This is the
zone where surface water leaches into the layers below.
B B Horizon: subsoil (aka regolith). Layer immediately below the topsoil.
This layer gets nutrients through the process known as LEACHING, LEACHING, when water flows through the topsoil and pulls nutrients down with it.
C C Horizon: partially weathered rock. This is the bottom layer of soil. Below it is solid bedrock.
Life in Soil
Some organisms mix the soil and make spaces in it for air and water.
Other soil organisms make humus, the material that makes soil fertile. Humus forms through decomposition. Fertile soil is rich in nutrients that plants
need.
Soil Conservation Soil is one of Earth’s most valuable
resourcesresources because everything that lives on the land depends directly or indirectly on soil.
FertileFertile soil is valuable because there is a limited supply. Less than 1/81/8thth of the land on Earth has soils well
suited for farmingfarming.
Soil Damage and Loss Soil can become exhausted, or lose its fertility. Accelerated Soil Erosion Unwise Clearing Clearing and Farming Farming methods increase soil erosion. For example,
clearing forests forests and containing animals to small pastures small pastures destroys the soil protection of plants
Soil Lost To The Seas!!
Three Examples of Accelerated Soil Erosion: DeforestationDeforestation - ( clearing trees )
GullyingGullying – furrows in plowed land which causes water to run faster over the soil
Climate ChangesClimate Changes – excessive rain or wind
Soil Conservation IntercroppingIntercropping: crops planted in alternating bands Contour PlowingContour Plowing: soil plowed in circular motion with the lay of the
land TerracingTerracing: step-like ridges in sides of hills Crop RotationCrop Rotation: planting one crop one year and a different one next
year
Contour Plowing
Contour plowing is the practice of plowing fields along the contours of a slope.
This helps slow the runoff of excess rainfall and prevents it from washing the soil away.
Conservation Plowing
Conservation Plowing disturbs the soil and its plant cover as little as possible.
Dead weeds and stalks of the previous year’s crop are left in the ground to help return soil nutrients.
Definition: - Transporting or moving weathered sediments
Driving Force: GRAVITYGRAVITY
GLACIERSGLACIERS•Unsorted & loose
•Scratched•Polished•U- shape valleys
WATERWATER•#1 agent•Well sorted•Smooth •Rounded
GRAVITYGRAVITY•Unsorted•Mass wasting•Creep •Slump•Talus
HumansHumans•Farming•Mining•Deforestation
WAVESWAVES•Beaches•Longshore current•Jetties & Groins
WINDWIND•Arid Deserts•Dunes•Pitted/frosted
Created by L. Zimmerman
Erosion by Gravity
•The movement of SOILSOIL particles and RockRock fragments is called MASS MASS
WastingWasting.
•TALUS :TALUS : rock fragments that gather at the bottom of the slope.
• Rapid Mass Movements
• ROCKFALLROCKFALL: rocks falling from a steep cliff
•ROCK SLIDEROCK SLIDE: loose rock and soil moving down a slope
•MUD FLOWMUD FLOW: rapid movement of mud
•SLUMPSLUMP: large block of soil moving downhill in one piece
Created by L. Zimmerman
Erosion by Gravity
MUDSLIDEMUDSLIDE
Created by L. Zimmerman
Erosion by Gravity
SlumpSlump
Talus SlopeTalus Slope
Created by L. Zimmerman
Erosion by wind
Deposition
Factors affecting Factors affecting DepositionDeposition: :
SIZE SIZE VelocityVelocity
ShapeShape Gradient Gradient Density Density
DischargeDischarge
Water Deposits•Well Sorted•Rounded
•Smooth•Abrasion
Vertical SortingVertical Sorting – In a quiet body of waterLoss of velocityBig gets dropped first
Horizontal SortingHorizontal Sorting – Stream enters lakeLoses velocitySediments depositedBig – close to shoreSmall – Far from shore
The settling or dropping of particles after being picked up by an agent of erosion Wind works the same way
Created by L. Zimmerman
DepositionSizeSize – As the size of sediment increases, the rate of
deposition increases.
Created by L. Zimmerman
Deposition
DensityDensity – As the density of sediment increases, the rate of deposition increases.
ShapeShape – The flatter the particle the slower the deposition.
Created by L. Zimmerman
As Velocity goes upup – Erosion goes upup and Deposition goes downdown
As Gradient gets steepersteeper – Erosion goes upup and Deposition goes downdown
As Discharge increasesincreases – Erosion goes upup.
Deposition
Deposition
When a stream enters a body of water, its speed will decrease, and therefore the deposition of sediments occurs.A deposit at the mouth of
a stream where it enters a large body of water is called a delta.
Created by L. Zimmerman
A delta is an example of the horizontal deposition of sediments in the water.
Clay
Boulders Cobbles
PebblesEvidence of Sorted Sediment
Deposition
Created by L. Zimmerman
Wind DepositsWind Deposits
•Similar to water
•Loss of velocity will result in deposition by size
•Well sorted
•Graded bedding
Velocity = FAST - ErosionVelocity = FAST - Erosion
Velocity = Slow - DepositionVelocity = Slow - Deposition
Erosional/Depostional Systems
RIVERS
YOUNGYOUNG
OLDOLD
MATUREMATURE
V shaped valley
Fast
Steep
Straight
Rapids & Waterfalls
Medium slope
Slight curves
Medium speed
Narrow floodplain
Small rapids
Flat
Slow
Lots of meanders
Straight
Wide floodplain & Channel
Created by L. Zimmerman
Erosional/Depositional Systems - Rivers
Created by L. Zimmerman
The bends in a stream’s channel are called meanders
Erosional/Depositional Systems - Rivers
Created by L. Zimmerman
Erosional/Depositional Systems - Rivers
Arial Map View of a stream Channel
Created by L. Zimmerman
Outside of the curve= velocity increase = more erosion.
Inside of the curve= velocity decrease = deposition.
Erosional/Depositional Systems - Rivers
Created by L. Zimmerman
DepositionDeposition
ErosionErosion
Erosional/Depositional Systems - Rivers
Created by L. Zimmerman
Formation of Oxbow Lake – the work of erosion and deposition
Erosional/Depositional Systems - Rivers
Created by L. Zimmerman
Erosional/Depositional Systems - Glaciers Glaciers can really
move a lot of materialmove a lot of material, dramatically changing the surface of the earth.
2 Types:2 Types:
Continental – covered North America over 10,000 years ago and is the cause of finger cause of finger lakes and Morraines lakes and Morraines (like Long Island)!(like Long Island)!
Alpine – in mountains Create U-ShapedU-Shaped valleys
Created by L. Zimmerman
Erosional/Depositional Systems - Glaciers
Created by L. Zimmerman
Erosional/Depositional Systems - GlaciersContinental GlacierContinental Glacier
GLACIERSFeatures:
Alpine GlacierAlpine Glacier
Unsorted, loose depositsGround up rock flour or glacial tillMorainesU-shape ValleysKettle lakes, drumlins, outwash plains
Moved from the north (pole) to the south
Move downhill!
Created by L. Zimmerman
Erosional/Depositional Systems - Glaciers Glacial Features
A. Terminal Moraine
B. Lateral Moraine
C. Glacial stream
D. Outwash plains
E. Braided streams
F. U- Shaped Valleys
Created by L. Zimmerman
Erosional/Depositional Systems - Glaciers
During Glaciation
Post - Glaciation
Its a U shape valley!Its a U shape valley!
Created by L. Zimmerman
Drumlins
Created by L. Zimmerman
Formation of Long Island
Formation of Formation of Finger LakesFinger Lakes
Created by L. Zimmerman
Landscape Development
How is the Earth’s surface shaped by weathering, erosion and deposition?
Created by L. Zimmerman
Landscape Development
Landscape: A region on the Earth’s surface in which physical features, such as hills, valleys, and streams are related by a common origin (it simply means “scenery”)
Three (3) main types: Mountains, Plains and PlateausMountains, Plains and Plateaus
Created by L. Zimmerman
Landscape Development
MountainsMountains
Greatest relief between their peaks and valleys
Created by tectonic forces (igneous and metamorphic rocks)
Steep mountain slopes have fast erosive streams acting on them, creating deep valleys and waterfalls
Created by L. Zimmerman
Landscape DevelopmentPlateaus
Low relief (flat) High elevation Horizontal rock formations
NC Piedmont
Created by L. Zimmerman
Landscape Development
Plains (lowlands)Plains (lowlands) Have the least relief Generally flat and low elevations Underlain by flat layers of sedimentary rock
HumansHumans
Tectonic ForcesTectonic Forces
ClimateClimate
TimeTime
Crustal MaterialsCrustal Materials
Humid
LANDSCAPELANDSCAPE
DEVELOPMENTDEVELOPMENT
ARIDARID