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3 Cards in this Set
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What are the formation and characteristics of igneous rocks? |
• A release of pressure causes magma to travel up a line of weakness.
• Magma forces rocks in the crust aside and forms an igneous intrusion. Magma takes the place of the existing rocks into the crust.
• Magma sometimes flows into the surface as lava = extrusive igneous rock. |
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Characteristics of igneous rock: |
• Igneous rocks are crystalline = because molten magma is consisted of a mixture of elements such as; silicia, iron & magnesium.
• When magma has cooled, combined elements form crystals and minerals.
• If it cools slowly = large crystals. Quickly = small crystals (microscopic).
• One big mass and do not have layers. |
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What are the types of igneous rocks? |
Granite: Crystals = Quartz, Mica and Feldspar. • Quartz = glassy, mica = black & flaky, feldspar = large white or pink.
Granite is intrusive igneous rock and magma cools slowly inside the earths crust. |
