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Chapter 2 Section 2
Question | Answer |
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Describe THREE ways Ingeous Rock is formed. | Composition: Fluids combine with rock, lowers melting point. Temperature: Rises then some rocks melt and some stay solid. Pressure: Pressure is applied, rocks form changes or it melts. |
How does the cooling rate of magma affect the rocks texture? | Longer time = More time for crystals to grow = Coarse-grained. Short time = Less time for crystals to grow = Fine-grained. |
Explain how intrusive igneous rock is formed. | Magma pushes into surrounding rock below the Earth's surface and cools then becomes intrusive igneous rock. |
Explain how extrusive rock is formed. | It is igneous rock that forms from magma that erupts. Common around volcanoes and has very small or no crystals. |
What are fissures? | Long cracks in the Earth's crust where lava flows. |
What determines the texture of igneous rocks? | The cooling rate of magma. |
What is the difference between a dike and a sill? | Dikes are sheetlike and they cut across previous rock units. Sills are sheetlike and are parallel to previous rock units. |
An igneous rock forms from slow-cooling magma deep beneath the surface of the Earth. What type of texture is this rock most likely to have? Explain. | The rock is most like to be coarse-grained because the crystals would have more time to grow. |