EXTRUSIVE VULCANICITY

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EXTRUSIVE VULCANICITY
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What is extrusive vulcanicity?
It is the range of processes by which

• lava

• superheated water

• solid materials

• gaseous materials

are ejected onto earths surface
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Features produced
1. Volcanoes
2. Lava plateaus
3. Hot springs
4. Geysers
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Parts of a volcano
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The crater
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Question Describe the distribution pattern of
volcanic zones
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3 major belts
1. Circum-Pacific Ring of Fire
2. Mediterranean-East African Belt
3. Mid-Atlantic Belt
http//vulcan.wr.usgs.gov/Volcanoes
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Types of volcanoes classified according to
shape and eruption power of volcanoes
1. Ash cinder cone
2. Acid lava cone
3. Basic lava cone
4. Composite cone
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Ash Cinder cone
What are their characteristics?
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Shape
Steep slope, Conical shape
Violent
Eruption
Ejected materials
Lava ejected to great height And broke into ash
and cinders
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Example of ash and cinder cone Paricutin
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Acid lava cone
What are their characteristics?
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Steep slope, great height
Shape
violent
Eruption
Ejected materials
Viscous lava
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Basic Lava Cone
What are their characteristics?
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Shape
Broad base, gentle slope, low height
Eruption
Non-violent
Fluid lava
Ejected materials
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Example of basic lava cone Mauna Loa
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Composite cone
What are their characteristics?
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Shape
Very great height, steep slope, With secondary
cones
Eruption
Violent
Ejected materials
Successive layers Of ash and lava
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An example of composite cone Alaska
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