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Types of Rock

Metamorphic
1. The new rocks are harder and more compact (e.g. Limestone → Marble, Clay → Slate).
2. Magma heats the rock in the crust.
3. Tectonic plates collide and the build up of heat and pressure causes rock to change.
4. Pressure from weight of material above changes rocks deep in the Earth.
Sedimentary
1. Layers of sediment compacted together (called lithification)
2. Clays/ Shales
  1. Formed from eroded mud and clay.
  2. Older rocks are deposited in layers and compacted.
3. Carboniferous Limestone/ Chalk
  1. Formed from Calcium Carbonate.
  2. Shells and dead sea creature skeletons deposited on sea bed and compacted over time.
4. Soft so may break apart or crumble easily
  1. Usually the only type to contain fossils
Igneous
1. Intrusive
  1. e.g. Granite
  2. Below Earth's surface.
  3. Large domes of cooled magma from large domes of igneous rock called bathothiths.
  4. Cools slowly.
    1. Large crystals and coarse texture.
  5. Magma flows into gaps in surrounding rock and forms dykes (vertical gaps) and sills (horizontal gaps).
2. Extrusive
  1. e.g. Basalt
  2. After erupted from volcano onto Earth's surface.
  3. Cools quickly.
    1. Small crystals and fine texture.
3. Magma cools and hardens.
Geological Time Scale

Types of Rock

	Created by rebeccachelsea about 9 years ago