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Unit 4 surface processes and landscapes
 

Unit 4 surface processes and landscapes

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    Unit 4 surface processes and landscapes Unit 4 surface processes and landscapes Presentation Transcript

    • 3:00
    • Weathering the breaking of rock into smaller particles called sediment . Physical ( AKA – Mechanical ) – Abrasion – Frost Wedging – Plants – Exfoliation - Chemical – Carbonation – Oxidation – Hydration – Plant Acids – Acid Rain - =
    • Types of Weathering Physical –causes a rock to crack or break into pieces without changing it chemically
    • Weathering the breaking of rock into smaller particles called sediment . 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.
    • Weathering the breaking of rock into smaller particles called sediment . 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 – Plants – Exfoliation - Chemical – Carbonation – Oxidation – Hydration – Plant Acids – Acid Rain - =
    • Physical Weathering
      • Frost wedging
        • water seeps into the cracks in a rock and freezes causing the ice to expand .
    •  
    • Weathering the breaking of rock into smaller particles called sediment . 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.
    • Weathering the breaking of rock into smaller particles called sediment . 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 – 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.
    •  
    • Weathering the breaking of rock into smaller particles called sediment . 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 – 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
    • Weathering the breaking of rock into smaller particles called sediment . 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 – 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.
    • Weathering the breaking of rock into smaller particles called sediment . 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 – CO 2 + H 2 O form weak acid that dissolves limestone Oxidation – Hydration – Plant Acids – Acid Rain - =
    • Chemical Weathering
      • Oxidation - Water + Oxygen = Rust
    • Chemical Weathering
      • Hydration
    • Weathering the breaking of rock into smaller particles called sediment . 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 – CO 2 + H 2 O form weak acid that dissolves limestone Oxidation – Rust Hydration – Water dissolves mineral to clay Plant 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
    • Weathering the breaking of rock into smaller particles called sediment . 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 – CO 2 + H 2 O form weak acid that dissolves limestone Oxidation – Rust Hydration – Water dissolves mineral to clay Plant Acids – plants produce weak acid that dissolves rocks. Acid Rain – man-made! =
    • Physical Chemical Caves/Karst Clay Dissolved minerals (hard water) Abrasion – smooth & rounded The WEDGE Exfoliation Climate Rock Type Exposure Particle Size Time Key Vocabulary Concept Map Results in: Sediments (ESRT pg 6) Dissolved Minerals Soil (pg 6 & 7 ) Erosion (pg 8 ) Weathering 4 things that help: My Definition of Weathering Water
    • Rates of Weathering FAST SLOW Climate Temp & Moisture Cold/Warm & Dry Warm & Wet Rock Type Igneous & Metamorphic Sedimentary Shale/siltstone – conglomerate - limestone Sandstone Dolostone
    • Rates of Weathering Climate is the major factor that affects the rate of weathering
    • Rates 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
    • 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
    • Rates of Weathering Carpenter Falls shows differential weathering.
    • Rates of Weathering Niagara Falls
    • Rates of Weathering FAST SLOW Exposure And TIME Underground/lesstime Above Ground Particle Size Or Surface Area Large size or less surface area Small size or more surface area
    • Rates of Weathering Particle 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 notes Label your diagram and explain how caves form in limestone! Use a textbook – pg 310 - 311
    • Products of Weathering - Soil
      • Read pg 7 and complete the “Etch-a-Sketch” on pg 6 of the notes
        • You may need to use a text book for picture 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 transported sediments because of glaciation!
      Slide 49
    • Ahead to 6:25
    • Definition : - Transporting or moving weathered sediments Driving Force: GRAVITY
      • GLACIERS
      • Unsorted & loose
      • Scratched
        • Polished
        • U- shape valleys
      • WATER
      • #1 agent
      • Well sorted
      • Smooth
      • Rounded
      • GRAVITY
      • Unsorted
      • Mass wasting
      • Creep
      • Slump
      • Talus
      • Humans
      • Farming
      • Mining
      • Deforestation
      Transported Sediment = Click here Residual Sediment =
      • WAVES
      • Beaches
      • Longshore current
      • Jetties & Groins
      • WIND
      • Arid Deserts
      • Dunes
      • Pitted/frosted
      Erosion
    • Erosion by Gravity MUDSLIDE
    • Erosion by Gravity Slump Talus Slope
    • Erosion by wind
    • Deposition Factors affecting Deposition : SIZE Velocity Shape Gradient Density 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 Deposits
      • Similar to water
      • Loss of velocity will result in deposition by size
      • Well sorted
      • Graded bedding
      Velocity = FAST - Erosion Velocity = Slow - Deposition Skip to 60
    • Deposition
      • Size – As the size of sediment increases , the rate of deposition increases .
      Page 6 ESRT
    • Deposition
      • Density – As the density of sediment increases , the rate of deposition increases .
      • Shape – The flatter the particle the slower the deposition.
      • As Velocity goes up – Erosion goes up and Deposition goes down
      • As Gradient gets steeper – Erosion goes up and Deposition goes down
      • As Discharge increases – Erosion goes up .
      Deposition
    • Deposition Particle Size vs. Stream Velocity Page 6 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
    • Deposition A delta is an example of the horizontal deposition of sediments in the water. Clay Boulders Cobbles Pebbles Evidence of Sorted Sediment
    • Deposition
    • Deposition Factors affecting Deposition: SIZE Velocity Shape Gradient Density Discharge Water Deposits Well 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 YOUNG OLD MATURE 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
    • Erosional/Depositional Systems - Rivers
    • The bends in a stream’s channel are called meanders Erosional/Depositional Systems - Rivers
    • Erosional/Depositional Systems - Rivers Arial Map View of a stream Channel
    • Erosional/Depositional Systems - Rivers 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.
    • Erosional/Depositional Systems - Rivers Deposition Erosion
    • Erosional/Depositional Systems - Rivers Formation of Oxbow Lake – the work of erosion and deposition Oxbow Formation Part 1 Part 2 – Why?
    •  
    • Erosional/Depositional Systems - Glaciers
      • Glaciers can really move a lot of material , dramatically changing the surface of the earth.
      • 2 Types:
      • Continental – covered NYS over 10,000 years ago and is the cause of our “till” deposits, finger lakes and transported soils!
      • Alpine – in mountains
        • Create U-Shaped valleys
    • Erosional/Depositional Systems - Glaciers
    • Erosional/Depositional Systems - Glaciers Continental Glacier GLACIERS Features: Alpine Glacier Unsorted, loose deposits Ground up rock flour or glacial till Moraines U-shape Valleys Kettle lakes, drumlins, outwash plains Erratics – 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
      • Terminal Moraine
      • Lateral Moraine
      • Glacial stream
      • Outwash plains
      • Braided streams
      • U- Shaped Valleys
    • Erosional/Depositional Systems - Glaciers During Glaciation Post - Glaciation Holy Goodness – it’s a U shape valley!
    • The Work of Waves The 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 produces waves and currents that erode 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 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.
    • SURF
      • 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 up a strip of sediment at the coastline called a beach.
      • Beaches are composed of whatever sediment is available, but most beaches are composed of 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.
    • SPIT
    • Long Point, Lake Erie, Canada Long Shore Current
    • Rip Currents
    • Oregon Inlet – Nags Head, NC
      • During storms waves can be much more powerful than normal.
    • During these times the beach tends to erode more and the sand is carried back into the ocean. There it is usually deposited as underwater bars parallel to the shore.
    • If these sand bars rise above the average sea level winds will help to pile up sediment. When vegetation begins to grow and stabilize the 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 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 Plateaus
    • Landscape Development
      • Mountains
      • Greatest relief between their peaks and valleys
      • Created by tectonic forces (igneous and metamorphic rocks)
    • Landscape Development
      • Mountains
      • Steep mountain slopes have fast erosive streams acting on them, creating deep valleys and waterfalls
    • Landscape Region MOUNTAINS: Elevation: HIGH Slope: STEEP Common Rock Type: IGNEOUS/Metamorphic Unique Features: Rapids/waterfalls, steep gorges
    • Landscape Development
      • Plateaus
      • Low relief (flat)
      • High elevation
      • Horizontal rock formations
    • Landscape Development
      • Plateaus
      • Streams can cut steep valleys into plateaus and dissect them
      • Ex: Grand Canyon
        • Catskills, NY
    • Landscape Development
      • And our own Grand Canyon of the East
      • Letchworth 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 Canyons LOW relief
    • Landscape Development
      • Plains (lowlands)
      • Have the least relief
      • Generally flat and low elevations
      • Underlain by flat layers of sedimentary rock
    • Landscape Region LOWLANDS (PLAINS): Elevation: LOW Slope: FLAT Common Rock Type: Sedimentary Unique Features: Found along lakes/shorelines and rivers
    • Humans Tectonic Forces Climate Time Crustal Materials Humid LANDSCAPE DEVELOPMENT ARID 97
    • Tectonics Tectonic activity is an “earth-building” activity
    • Folding and Faulting
    • 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 82
    • Landscape Development The Niagara escarpment is the exposed edge of a large scale syncline (geosyncline). = Limestone and Dolostone
    • Landscape Development In Ontario, the Niagara Escarpment has been formed by differential erosion. = Limestone Hard!
    • Landscape Development Where rivers cross the escarpment, waterfalls may be formed by undercutting .
    • Some QUITE Spectacular!
    • Landscape Development
      • 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
    • Landscape Development
      • How does landscape affect stream drainage patterns?
      • Landscape determines how a river will flow and what it will erode!
    • Landscape Development
      • Stream Drainage Patterns
    • Landscape Development
      • 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
      82
    • Landscape Development
      • Humans effect on landscape has been profound
      • Farming, mining and construction can cause severe erosion
      84
    • Landscape Development
      • 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
      84
    • Landscape Development
      • 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 determined prior to glaciation, however glaciers modified the landscape.