Rock Types
- Created by: Ashleigh Hockenhull
- Created on: 25-03-15 16:42
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- Types of Rock
- Igneous Rocks
- Formed from magma that's cooled down
- Intrusive igneous rocks
- 1. form when magma cools down below earth's surface
- 2. magma cools down very slowly, forming large crystals - give rocks coarse texture
- 3. large domes of cooled magma form domes of igneous rock - batholiths
- 4. where magma has flowed into gaps in surrounding rock it forms dykes and sills
- 3. large domes of cooled magma form domes of igneous rock - batholiths
- 2. magma cools down very slowly, forming large crystals - give rocks coarse texture
- 1. form when magma cools down below earth's surface
- extrusive igneous rocks
- 1. form when magma cools down after erupted from a volcano onto earth's surface
- 2. magma cools down very quickly, forming small crystals that give the rocks a fine texture
- 1. form when magma cools down after erupted from a volcano onto earth's surface
- composed of interlocking crystals - generally tough rocks & resistant to erosion
- Sedimentary Rocks
- formed when layers of sediment are compacted together until they become solid rock
- usually form layers called beds
- often contain fossils
- although some rocks are tough, most weaker than igneous & metamorphic rocks
- Metamorphic rocks
- formed by heat and pressure
- 1. rocks deep in the earth are changed by pressure from the weight of material above them
- when tectonic plates collide, rocks are changed by massive heat & pressure that builds up
- 3. magma from mantle heats the rocks in crust, causing them to change
- when tectonic plates collide, rocks are changed by massive heat & pressure that builds up
- crystalline
- often exibit layering called cleavage & banding
- tend to be very tough & resistant to erosion
- Igneous Rocks
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