Weathering, Erosion, & Deposition by lXK4rdzv

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									 Weathering, Erosion, & Deposition

 What are the effects of
weathering, erosion, and
   deposition on the
 environment in Texas
    How does weathering, erosion, &
    deposition act together in a cycle
    that changes the Earth’s surface?

 Weathering-breaks down the Earth’s surface
 Erosion - moves the Earth’s surface
 Deposition - builds up the earth’s surface

   Please draw the cycle


Deposition           Erosion
                What is Weathering?

   The breaking down of rocks into smaller pieces

 Must occur before erosion can
 No movement is involved
 Sediments- small/tiny pieces
 of weathered down rock.
             What is Physical Weathering?

 Physical/Mechanical            weathering …
 the breaking down of rocks into smaller pieces (wind, flowing
  water, ice, gravity, animals/plants, temperature changes)

    Physical Weathering -- The steep walls here   Palo Duro Canyon in the High
         were carved out by moving water                Plains Eco-Region
               Physical Weathering

Enchanted Rock in the Llano
     Uplift Eco-region
                              Exfoliation-warming and cooling
                              of rocks over time causes rocks
                              to peel into sheets
             What is Chemical Weathering?

 Chemical   weathering …
  dissolving and changing the minerals in rocks into new ones.
(Oxidation-Rusting & Acid breakdown)

                                           This cave was formed by
                                             slightly acidic water
                                           dissolving the limestone
                Chemical Weathering

Natural Bridge Caverns in Texas
                 Let’s Compare!

   Please draw a Venn diagram and compare
    chemical and physical weathering.
   How are they similar/different?

    Physical/Mechanical   Chemical
       Weathering         Weathering
                       What is Erosion?
   The movement of weathered earth materials
    by moving water, wind, gravity or ice
           Example                   Cause of Erosion
Waves eroding the beach and East         Water
TX shoreline
Desert Sandstorm in West TX from          Wind
Rain causing Mudslide in the         Water & Gravity
Rolling Hills of Central TX
Landslide on sides of Plateaus of        Gravity
Central TX
Rain carrying soil down a driveway   Water & Gravity
   Galveston Before and After Hurricane Ike
         How does Erosion form a gorge?

A gorge is a ravine with nearly vertical walls that had its
            sediment washed away by a river.
This gorge was cut with heavy rains pushed a flood over
       Canyon Lake Dam in central Texas in 2002.
How do Glaciers for a gorge?

           The Bernard Glacier in Alaska's
          Saint Elias Mountains looks like
                a huge alpine highway.
          Heat & Gravity allow Glaciers to
             move down a slope carrying
            away anything in their path—
          soil, rocks, & sides of mountains
               Why care about erosion?

 Humans have increased the rate of erosion 200 to 2,000 times
  faster than normal.
 What’s Speeding it Up?
 Removing plants that hold soil in plants, this exposes the land to
  wind/water erosion.
 Construction sites removes plants, soil, minerals, & nutrients.
  Replaced by concrete that increases flooding from surface runoff.
How does removing plants effect the erosion on the
              left side of the hill?
  How does keeping plants effect the erosion on the
               right side of the hill?

             • Mudslide danger
         • Loss of topsoil
    • Clogged storm drains
    • Flooding problems
    • Expensive clean up
• Eroded or buried
  house foundations
           • Mudslide danger   • Soil in place
           • Loss of topsoil       • Less clean up
      • Clogged storm drains             • Minimum erosion
  • Flooding problems                        • Protection
  • Expensive clean up                           for house
  • Eroded or buried                               foundations
house foundations
                  What are landslides?

Landslides – Movement of sediment down hill due to gravity.
Example: Rock falls on the edges of plateaus & cliffs.
       What is Deposition?

   When eroded sediments are deposited in a new location
   Example: delta -- where sediment is deposited where
    a river flows into an ocean or lake builds up a landform

                   Before               After

              W. Texas Example
            Desert winds sculpted
          these gentle swirls out of
         the limestone hills in Black
         Gap Wildlife Management
          Area, Texas. This remote,
         100,000-acre area in West
           Texas contains some of
           the lowest, driest, and
             hottest areas in the
             Chihuahuan Desert

                            Deposition area from the
                               Rio Grande River

   The Red River carries
sediments, and drops some
      along the way
Let’s Practice, write in your S.J. what
    type of erosion shaped these
      Water, Wind, Gravity, Ice?

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