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EXTRUSIVE VOLCANIC FEATURES First Form Prepared by: Mrs. L. Greenidge. These are formed on the Earth 's surface when lava cools and hardens. Examples of Extrusive features. Volcanic cones are examples of extrusive features. TYPES OF VOLCANIC CONES.
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EXTRUSIVE VOLCANIC FEATURESFirst FormPrepared by: Mrs. L. Greenidge These are formed on the Earth 's surface when lava cools and hardens.
Examples of Extrusive features Volcanic cones are examples of extrusive features.
TYPES OF VOLCANIC CONES There are three main types of volcanic cones: 1. Lava cones 2. Cinder cones 3. Composite cones
LAVA CONES Lava cones are formed when lava hardens on the volcano. There are two types of lava cones: 1. Acid lava cones also known as lava domes 2. Basic lava cones also known as shield cones
CINDER CONES When gas-charged lava is blown violently into the air, it breaks into small pieces that harden and fall as cinders around the vent to form a circular cone.
COMPOSITE CONES Are formed from alternate layers of ash and lava. Each eruption begins with great force, throwing out ash. Lava then pours out, forming layers on top of the ash. Composite cones are steep sided.
SUMMARY Volcanic cones are extrusive features. Lava, cinder & composite are types of volcanic cones. Lava cones are either acidic or basic. Acid lava flows slowly, hardens quickly & creates steep slopes. Basic lava flows quickly & creates gentle slopes. Cinder cones form from lava that breaks into small pieces and creates a steep slope. Composite cones form from lava & ash and are steep.
ASSESSMENT Using open office writer on your netbooks, name the correct type of volcanic cone described in each poem.
1. My name is La Soufriere, from SVG a beautiful isle If you want to climb me its sure to take a while, My sides are very steep you see You won't make it up with a bad knee, Plus I'm big & bad, you better beware With my friends lava & ash I'll fill you with fear, So my question to you and don't be shy What type of volcanic cone am I?
2. Sometimes I move so very slow It seems that I can hardly go, And by the time the air hits me You will see me harden so very quickly, I stand up high, so steep and tall Who would want to climb me at all, Well my question to you and don't be shy What type of volcanic cone am I?
3. Can't you see I flow free like water? Don't you know its destruction I'm after? Even my sides are a whole lot gentler Just so that you can come a little closer, Go on, take a peek inside my head All you will see is RED RED RED, Now my question to you and don't be shy What type of volcanic cone am I?
4. All charged up and ready to blow Look up in the sky and see me go, But wait a minute, how did I get so small? I'm breaking into pieces, getting hard as I fall, I build up myself with tiny pieces of stone And when I'm done I have a circular cone, So my question to you and don't be shy What type of volcanic cone am I?
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Assignment Using your netbooks: 1. Research examples of the different types of volcanic cones found throughout the world. Name one example for each type of volcanic cone. 2. Save a picture of each type of volcanic cone you find as your example. (right click on the picture and choose “save image” and save in your pictures folder.