What are the effects of weathering, erosion, and

deposition on the environment in Texas

Eco-regions?

Weathering, Erosion, & Deposition

Weathering-breaks down the Earth’s surface

Erosion - moves the Earth’s surface

Deposition - builds up the earth’s surface

fc2.galenaparkisd.com

How does weathering, erosion, & deposition act together in a cycle that changes the Earth’s surface?

Please draw the cycle

Weathering

ErosionDeposition

Must occur before erosion can happen

No movement is involved

Sediments- small/tiny pieces of weathered down rock.

The breaking down of rocks into smaller pieces

What is Weathering?

Physical/Mechanical weathering …

the breaking down of rocks into smaller pieces (wind, flowingwater, ice, gravity, animals/plants, temperature changes)

Physical Weathering -- The steep walls here were carved out by moving water

Palo Duro Canyon in the High Plains Eco-Region

What is Physical Weathering?

Enchanted Rock in the Llano Uplift Eco-region

Exfoliation-warming and cooling of rocks over time causes rocks to peel into sheets

Physical Weathering

This cave was formed by slightly acidic water

dissolving the limestone

Chemical weathering …

dissolving and changing the minerals in rocks into new ones.

(Oxidation-Rusting & Acid breakdown)

What is Chemical Weathering?

Natural Bridge Caverns in Texas

Chemical Weathering

Please draw a Venn diagram and compare chemical and physical weathering.

How are they similar/different?

Physical/Mechanical ChemicalWeathering Weathering

Let’s Compare!

Example Cause of Erosion

Waves eroding the beach and East TX shoreline

Water

Desert Sandstorm in West TX from drought

Wind

Rain causing Mudslide in the Rolling Hills of Central TX

Water & Gravity

Landslide on sides of Plateaus of Central TX

Gravity

Rain carrying soil down a driveway Water & Gravity

The movement of weathered earth materials by moving water, wind, gravity or ice

What is Erosion?

Erosion Galveston Before and After Hurricane Ike

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 does Erosion form 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

How do Glaciers for a gorge?

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.

Why care about erosion?

How does removing plants effect the erosion on the left side of the hill?

• Mudslide danger• Loss of topsoil

• Clogged storm drains• Flooding problems• Expensive clean up

• Eroded or buried house foundations

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

• Soil in place• Less clean up

• Minimum erosion• Protection

for housefoundations

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

What are landslides?

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

What is Deposition?

W. Texas ExampleDesert 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

Deposition area from the

Rio Grande River

The Red River carries sediments, and drops some

along the way

Deposition

Let’s Practice, write in your S.J. what type of erosion shaped these

landforms!Water, Wind, Gravity, Ice?