Weathering Weathering Students will be able to describe and give examples of chemical and physical...
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Transcript of Weathering Weathering Students will be able to describe and give examples of chemical and physical...
WeatheringWeathering Students will be able to
describe and give examples of chemical
and physical weathering.
Weathering• The breakdown of materials on Earth’s
crust into smaller pieces.
Two Types of WeatheringVenn Diagram
• Mechanical Weathering
• Chemical Weathering
Mechanical Weathering• Process by which rocks are broken down
into smaller pieces by external conditions.• Types of Mechanical Weathering
– Frost Action• Ice Wedging
– Wind– Water– Abrasion– Plant growth– Animals
Ice wedging: water is confined in cracks or pores then freezing on the rock surface and
downward into the rock, solidifying and expanding deeper inside, thus wedging the
rocks apart.
Ice Wedging
Ice wedging slowly breaks up this sedimentary rock into
unusual shapes.
Abrasion• Water
• Moves rocks, making them hit each other
• Wind• Blows sand against rocks
• Gravity• Rocks rub against each other as
they slide downhill
These rocks have been blasted by wind and sand causing them to
become rounded.WIND
Water• Rivers, streams, and runoff
This is a picture of the Half
Dome. The rock is peeling away
from the mountain in
layers just like an onion. This is exfoliation.
(Abrasion)
Plant Growth
Plant growth
The tree is growing in the
rock and soon the rock will break
apart because of the tree roots.
Animals
Chemical Weathering
• The process that breaks down rock through chemical changes. Greatest in warm/wet environments.
• The agents of chemical weathering– Water– Acid in ground water– Living organisms– Acid Precipitation (rain, snow)– Oxygen
Water
• Water weathers rock by dissolving it
Acids in Groundwater: Caves and caverns typically form in limestone
stalactites - hang from ceiling stalagmites - on the ground
The lichen covered boulder produces a habitat for mosses and eventually higher
plants which continue the breakdown of the rock surface by producing weak acids.
Acid Precipitation
1908 to 1969
Acid precipitation has eaten away this limestone statue. Rain, sleet, ice snow, that contains a high concentration of
acids.
Oxygen the second most common element in the air we
breathe, reacts with iron in minerals to form iron oxide minerals, e.g. hematite (rust). As many minerals
contain iron, it is not unusual to see red-colored rocks like the example from Arches National Park shown
here.
Weathering and Erosion Video1. What is an example of weathering and erosion in the restroom?2. Weathering means _________________. Erosion means
____________________.3. What 3 ways does water cause weathering?
1.2.3.
4. What are the 2 types of weathering?1.2.
5. What are the 2 types of erosion?1.2.
https://youtu.be/exS9gFXgib0
Karst Topography• A type of landscape in rainy regions where
there is limestone near the surface, characterized by caves, sinkholes, and disappearing streams.
• Created by chemical weathering of limestone
Karst Topography Video1. What are karst topography examples?2. Why is pollution of karst land forms harmful to the
environment?3. Where are there a lot of karst environments?4. How does pollution affect cave systems outside of urban
environments?5. What university is the leader in karst topography
research?6. Where can you find materials on karst topography
online?
https://www.youtube.com/watch?v=DBUZLNIlAmg
Features of Karst: Sinkholes
Features of Karst: Caves
Features of Karst: Disappearing Streams