unit 4 surface processes and landscapes

Created by L. Zimmerman

Physical (AKA – Mechanical) –

Abrasion –

Frost Wedging –

Plants –

Exfoliation -

Chemical –

Carbonation –

Oxidation –

Hydration –

Plant Acids –

Acid Rain -

the breaking of rock into smaller particles called sediment.

Types of WeatheringTypes of Weathering

Physical –causes a rock to crack or break into pieces without changing it chemically

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 –

Plant Acids –

Acid Rain -

Physical Weathering

Abrasion sediments carried by streams and wind blown

sand cause particles to collide into each other and the surrounding rock.

chemically

Abrasion – Bump & Grind (streams/wind) smooth rounded particlesFrost Wedging –

Plants –

Exfoliation -

Chemical –

Carbonation –

Oxidation –

Hydration –

Plant Acids –

Acid Rain -

Physical WeatheringFrost wedging

water seeps into the cracks in a rock and freezes causing the ice to expand.

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 –

Hydration –

Plant Acids –

Acid Rain -

Physical Weathering

Plants Trees and shrubs can

grow through cracks in rocks.

Their roots wedge into crevices.

Abrasion – Bump & Grind (streams/wind)

Plants – roots wedge into rock and grow (expand)

Exfoliation -

Chemical –

Carbonation –

Oxidation –

Hydration –

Plant Acids –

Acid Rain -

Physical Weathering

Exfoliation –cycle of heating and cooling causes the rock to expand & contract so it breaks off in slabs or layers.

Abrasion – Bump & Grind (streams/wind)

Plants – roots wedge into rock and grow (expand)

Exfoliation – Freeze & Thaw causes rock to “peel”

Chemical –

Carbonation –

Oxidation –

Hydration –

Plant Acids –

Acid Rain -

Chemical – Any process that causes rocks to breakdown by chemical action and results in a change in the minerals (chemical composition).

Types of Weathering

chemically

Abrasion –

Frost Wedging –

Plants –

Exfoliation -

Chemical – involves water + it changes the rocks chemical composition

Carbonation –

Oxidation –

Hydration –

Plant Acids –

Acid Rain -

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.

chemically

Abrasion –

Frost Wedging –

Plants –

Exfoliation -

Carbonation – CO2 + H2O form weak acid that dissolves limestoneOxidation –

Hydration –

Plant Acids –

Acid Rain -

=the breaking of rock into smaller particles called sediment.

Chemical Weathering

Oxidation - Water + Oxygen = Rust

Chemical Weathering

Hydration

chemically

Abrasion –

Frost Wedging –

Plants –

Exfoliation -

Carbonation – CO2 + H2O form weak acid that dissolves limestoneOxidation – RustHydration – Water dissolves mineral to clayPlant Acids –

Acid Rain -

Chemical Weathering

Plant Acids – Plants produce weak acids that dissolve minerals in a rock, weakening the rock.

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

chemically

Abrasion –

Frost Wedging –

Plants –

Exfoliation -

Carbonation – CO2 + H2O form weak acid that dissolves limestoneOxidation – RustHydration – Water dissolves mineral to clayPlant Acids – plants produce weak acid that dissolves rocks.Acid Rain – man-made!

Results in:Sediments (ESRT pg 6)Dissolved MineralsSoil (pg 6 & 7 )Erosion (pg 8 )

Weathering

4 things that help:

My Definition of Weathering

Physic

Chemical

Caves/Caves/KarstKarst

ClayClay

Dissolved Dissolved minerals minerals

(hard (hard water)water)

Abrasion – Abrasion – smooth & smooth & roundedrounded

The The WEDGEWEDGE

ExfoliationExfoliation

Climate

Rock TypeExposure

Particle SizeTime

Rates of Weathering

FAST SLOW

ClimateTemp & Temp & MoistureMoisture

Cold/Warm & DryCold/Warm & DryWarm & WetWarm & Wet

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

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

Carpenter Falls shows differential weathering.

Rates of Weathering

Niagara Falls

Rates of Weatheri

ngFAST SLOW

ExposureAnd And TIMETIME

Underground/Underground/lesstimelesstime

Above GroundAbove Ground

Particle Size Or Surface

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, too small to be seen with an ordinary microscope, and too light to settle in water.

• Even in calm water, they remain suspended within the water.

Size by name and number is in ESRT pg 6

Products of Weathering

In western New York that 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.

Carlsbad Cavern, New Mexico

Sinkhole - Florida

Formation of Caverns – pg 5 in pg 5 in notesnotes

Label your diagram and explain how caves form in limestone!

Use a textbook – pg 310 - 311Use a textbook – pg 310 - 311

Products of Weathering - Soil

Read pg 7 and Read pg 7 and complete the complete the “Etch-a-Sketch” on “Etch-a-Sketch” on pg 6 of the notespg 6 of the notes

• You may need You may need to use a text to use a text book for picture book for picture ideas.ideas.

Residual Vs. Transported

• If the soil does not match the parent rock is transported

• if the sediments match the parent rock the soil is residual.

• NYS has mostly NYS has mostly transported transported sediments because of sediments because of glaciation!glaciation! Slide 49

Created by L. ZimmermanAhead to 6:25

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

Transported Sediment =

Click here

Residual Sediment =

WAVESWAVES•Beaches•Longshore current•Jetties & Groins

WINDWIND•Arid Deserts•Dunes•Pitted/frosted

Erosion by Gravity

MUDSLIDEMUDSLIDE

Erosion by Gravity

SlumpSlump

Talus SlopeTalus Slope

Erosion by wind

Deposition

Factors affecting Factors affecting DepositionDeposition: :

SIZE SIZE VelocityVelocity

ShapeShape Gradient GradientDensityDensity Discharge Discharge

Water Deposits•Well Sorted•Rounded

•Smooth•Abrasion

Vertical Sorting - Horizontal Sorting

The settling or dropping of particles after being picked up by an agent of erosion

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 - DepositionSkip to 60

DepositionSizeSize – As the size of sediment increases, the rate of

deposition increases.

Deposition

DensityDensity – As the density of sediment increases, the rate of deposition increases.

ShapeShape – The flatter the particle the slower the deposition.

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 Particle Size vs. Stream Velocity

of ESRT

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.

The Mississippi Delta

A delta is an example of the horizontal deposition of sediments in the water.

Boulders Cobbles

PebblesEvidence of Sorted Sediment

Deposition

Factors affecting Deposition:

SIZE SIZE VelocityVelocity

ShapeShape Gradient GradientDensityDensity Discharge Discharge

Water DepositsWell sorted, round,

smooth, graded bedding

Vertical Sorting –mixed particles in order of big, medium, small due to changes in velocity

Horizontal Sorting – Occurs when a stream enters a large body of water &loses velocity

The settling or dropping of particles after being picked up by an agent of erosion

Back to 50

Erosional/Depostional Systems

RIVERS

YOUNGYOUNG

OLDOLD

MATUREMATURE

V shaped valley

Straight

Rapids & Waterfalls

Medium slope

Slight curves

Medium speed

Narrow floodplain

Small rapids

Lots of meanders

Straight

Wide floodplain & Channel

Erosional/Depositional Systems - Rivers

The bends in a stream’s channel are called meanders

Arial Map View of a stream Channel

At the outside of the curve, the stream velocity increases, therefore erosion occurs.

At the inside of the curve, the stream velocity decreases, therefore deposition occurs.

DepositionDeposition

ErosionErosion

Formation of Oxbow Lake – the work of erosion and deposition

Oxbow Formation Oxbow Formation

Part 1

Part 2 – Why?

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 NYS over 10,000 years ago and is the cause cause of our “till” deposits, of our “till” deposits, finger lakes and finger lakes and transported soils!transported soils!

Alpine – in mountains Create U-ShapedU-Shaped valleys

Erosional/Depositional Systems - Glaciers

Erosional/Depositional Systems - GlaciersContinental GlacierContinental Glacier

GLACIERSFeatures:

Alpine GlacierAlpine Glacier

Unsorted, loose depositsGround up rock flour or glacial tillMorainesU-shape ValleysKettle lakes, drumlins, outwash plainsErratics – large boulders that don’t match the natural bedrock

Moved from the north (pole) to the south

Move downhill!

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

Erosional/Depositional Systems - Glaciers

During Glaciation

Post - Glaciation

Holy Goodness – it’s a U Holy Goodness – it’s a U shape valley!shape valley!

The Work of WavesThe most important agent shaping coastal landforms is wave action.

And WHY do you need to know this? – because Long Island is in NYS!

As wind moves over the ocean, it As wind moves over the ocean, it produces waves and currents that erode produces waves and currents that erode the bordering land.the bordering land.

Waves can also be produced by underwater earthquakes and the effect of the moon in producing tides.

The height of a wind created wave depends on the length of time the wind blows and the Fetch.

Fetch is the length of open water over Fetch is the length of open water over which the wind blows.which the wind blows.

Normal winds rarely produce ocean waves higher than 15m.

Each particle moves in place in a circular motion.

This motion occurs below the surface as well, in smaller and smaller circles.

When waves enter shallow water near the shore, they drag against the bottom.

The waves then become unstable and water rushes toward the shore as breaking waves or surf.

Wave movement toward the shore often builds Wave movement toward the shore often builds up a strip of sediment at the coastline called a up a strip of sediment at the coastline called a beach.beach.

Beaches are composed of whatever sediment is Beaches are composed of whatever sediment is available, but most beaches are composed of available, but most beaches are composed of sand.sand.

Waves moving at an angle to the shoreline push water along the shore creating a longshore current.

A longshore current is a movement of water parallel to and near the shoreline.

Longshore currents transport sand in a direction parallel to the shoreline.

Sand moving along a relatively straight shore keeps moving until the shoreline changes direction.

This happens at bays and headlands.

Here the longshore current slows and sand is deposited at the near end of the headland.

A long narrow deposit of sand connected at one end to the shore is called a spit.

Long Point, Lake Erie, Canada

Long Shore Current

Rip Currents

Oregon Inlet – Nags Head, NC

During storms waves can be much During storms waves can be much more powerful than normal.more powerful than normal.

During these times the beach During these times the beach tends to erode more and the tends to erode more and the sand is carried back into the sand is carried back into the ocean.ocean.There it is usually deposited There it is usually deposited as underwater bars parallel as underwater bars parallel to the shore.to the shore.

If these sand bars rise above the average sea If these sand bars rise above the average sea level winds will help to pile up sediment.level winds will help to pile up sediment.

When vegetation begins to grow and stabilize the When vegetation begins to grow and stabilize the offshore sediment pile, a barrier island is created.offshore sediment pile, a barrier island is created.

Outer Banks, NC – Barrier Islands

Hatteras – Ocracoke Island, NC

Pamlico Sound (Land Side)

Atlantic Ocean – Sea Side

Barrier Island

Man-Made structures – Help or Hindrance? Groins and jetties are

built perpendicular to the shoreline.

Groins extend like fingers away from the shore.

Jetties are built where a river empties into ocean.

The Problem????

Landscape Development

How is the Earth’s surface shaped by weathering, erosion and deposition?

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

MountainsMountains

Greatest relief between their peaks and valleys

Created by tectonic forces (igneous and metamorphic rocks)

MountainsMountains

Steep mountain slopes have fast erosive streams acting on them, creating deep valleys and waterfalls

Landscape Region

MOUNTAINS:

Elevation:

HIGHSlope:

Common Rock Type:

IGNEOUS/Metamorphic

Unique Features:

Rapids/waterfalls, steep gorges

Plateaus

Low relief (flat)

High elevation

Horizontal rock formations

PlateausPlateaus

Streams can cut steep valleys into plateaus and dissect them

Ex: Grand Canyon Catskills, NY

And our own Grand Canyon of the East

Letchworth State ParkLetchworth State Park

Located on the Allegheny Plateau of New York State

Landscape Region

PLATEAU:

Elevation: Slope: Common Unique Rock Type: Features:

HIGH Elevation Flat Sedimentary CanyonsLOW relief

Plains (lowlands)Plains (lowlands)

Have the least relief

Generally flat and low elevations

Underlain by flat layers of sedimentary rock

Landscape Region

LOWLANDS (PLAINS):

Elevation:

Slope:

Common Rock Type:

Sedimentary

Unique Features:

Found along lakes/shorelines and rivers

HumansHumans

Tectonic ForcesTectonic Forces

ClimateClimate

TimeTime

Crustal MaterialsCrustal Materials

LANDSCAPELANDSCAPE

DEVELOPMENTDEVELOPMENT

ARIDARID

Sharon Johnson http://GeoImages.Berkeley.EDU.

Tectonics

Tectonic activity is an “earth-building” activity

Sharon Johnson http://GeoImages.Berkeley.EDU.

Folding and Faulting

http://www.geog.ouc.bc.ca/physgeog/contents/10l.html

Folding and Faulting

Folding is the process that bends and twists rocks, usually due to compression

Faulting is the process where rocks move past each other along a fracture

http://www4.vc-net.ne.jp/~klivo/gen/nmapeng.gif

The Niagara escarpment is the exposed edge of a large scale syncline (geosyncline). = Limestone and Dolostone

http://www4.vc-net.ne.jp/~klivo/gen/geology.htm

In Ontario, the Niagara Escarpment has been formed by differential erosion. = Limestone Hard!

Where rivers cross the escarpment, waterfalls may be formed by undercutting.

Some QUITE Spectacular!

Due to different rock types in the same area, the harder rock (competent) will form hills and ridges

Erosion of the weaker rock (incompetent) will make major valleys

Streams tend to follow areas of weaker rock

How does landscape affect stream drainage patterns? Landscape determines how a river will flow and

what it will erode!

Stream Drainage Patterns

CLIMATE is most influential in determining the rate of landscape development.

Arid Climate

Less water erosion More steep and angular

slopes. Shows fewer signs of

erosion

Humid Climate

More weathering More erosion More deposition Rounded hills Less steep slopes Promotes lush

vegetation

Humans effect on landscape has been profound

Farming, mining and construction can cause severe erosion

The stage of development of a landscape is determined by the duration of time it has been acted upon

Older landscapes show more effects of weathering and erosion

Landscapes of New York State (page 2 in reference table)

Most NYS soils are unsorted sediments deposited by the most recent continental glacier

Rock types and structures found in NYS were Rock types and structures found in NYS were determined prior to glaciation, however glaciers determined prior to glaciation, however glaciers modified the landscape.modified the landscape.

unit 4 surface processes and landscapes

weak carbonic

carbonic acid

form weak

erosionaldepositional

longshore

landscape

wind blows

deposition

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