Download Rocks, Weathering and Erosion

Rocks, Weathering and Erosion
define and provide examples of weathering and erosion
describe the three classes of rocks
Types of Rocks
● There are three types of rock categories based on their
composition and conditions of formation
○ Igneous
○ Sedimentary
○ Metamorphic
Igneous Rocks
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Igneous rock are the most abundant and are formed from molten magma from the
Earth’s mantle or from lava.
Igneous rocks have large crystals if the magma cools slowly while still being under
ground
Igneous rock have small crystals or a fine grain appearance, if the magma cools
quickly.
Most igneous rocks contain a various combinations of quartz, mica, olivine,
hornblende, pyroxene and two feldspars
Example: Basalt and Granite
Sedimentary Rocks
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Sedimentary Rocks are formed by the settling out of solid particles from air, water
or glacial ice into layers called sediments
The sediments are composed of rock particles, the remains of plants or animals or
a combination of the two
The sediments are cemented and compressed in a process called lithification,
which occurs as additional layers settle on top and apply additional pressure to
the lower layers forming a sedimentary rock
Example: Shale, Limestone and coal
Metamorphic Rocks
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Metamorphic rocks form from all other types of rocks that have undergone a
change in form due to high pressure and heat deep within the Earth’s crust or
mantle
Heat and pressure produce physical or chemical changes to the rocks,
compressing and transforming them.
Example: Marble, Slate, and Gneiss
Physical Weathering
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Weathering is a process by which rocks are broken down and altered by exposure
to environmental conditions
Physical or Mechanical Weathering is the weakening of rocks that does not involve
a chemical reactions
Alternating heating and cooling makes rocks expand and contract. When water
seeps into the cracks and pores, then freezes, thus expanding the cracks.
Plant roots enlarge and split open cracks into rocks
These all contribute to the weakening and breaking down large rock into smaller
pieces through weathering.
Chemical Weathering
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Chemical Weathering chemically alters the mineral components of rocks.
The action of oxygen from air and water causes an oxidation reaction
decomposing minerals, especially in the rocks that contain iron
When iron is found in combination with sulfur, it weakens the rock
When a reddish or yellowish stain is found that is also a product of oxidation
Rock Cycle
Videos
3 types Song
https://www.youtube.com/watch?v=jPgE74Vltdc
3 types of Rocks
https://www.youtube.com/watch?v=6bkyXvYP4jM
Erosion
https://www.hoopladigital.com/title/10028878 Bill Nye