Metaphoric rocks

• Metamorphic


  The rock has changed form
• Metamorphic rock formation


  1. Existing igneous and sedimentary rocks are altered by high temperature and pressure

  2. Metamorphic rocks can also be formed from other metamorphic rocks
• Metamorphic rocks


  • Rock changes into metamorphic form when it experiences intense heat and extreme pressure
  • Changes can be physical or chemical, and include the formation of new minerals not seen in igneous or sedimentary rocks
• Metamorphic rock formation


  • Occurs deep beneath the Earth's surface where the pressure is very high
  • Pressure alone may be enough to alter some rocks
  • Heat alone can alter rocks
• Movements within the Earth's crust


  Can cause extreme heat and pressure that leads to metamorphism
• Regional metamorphism


  Metamorphism over a wide area
• Contact metamorphism


  Metamorphism that occurs in rocks that come in contact with hot magma as it pushes through the mantle and crust
• Recrystallisation


  Heat and pressure can melt rock, causing new crystals to grow as the rock cools down
• Metamorphic rocks


  • Have many different minerals compared with igneous rocks
• Foliation


  1. Minerals in metamorphic rocks can become squashed into layers

  2. Minerals forming under pressure may become squashed flat or into long needle shapes
• Non-foliated or unbanded metamorphic rocks


  Metamorphic rocks without bands
• Rock cycle


  A model geologists use to explain the endless cycle of change that rocks undergo
• Rock cycle


  1. Weathering breaks rocks down into smaller pieces

  2. Pieces are carried away by agents of erosion (water, wind, ice)

  3. Pieces can be deposited as sediments and re-form into sedimentary rocks

  4. Any rock can also be melted by magma and turned into a metamorphic rock
• Types of metamorphic rocks


  There are two main types of metamorphic rocks: foliated and non-foliated. Foliated rocks have a layered or banded appearance, while non-foliated rocks do not.
• Examples of metamorphic rocks

  Examples of metamorphic rocks include gneiss, schist, slate, and marble.
• Rock cycle

  
• The process whereby rocks are broken down through weathering, transported by erosion, and then reformed into new rocks through processes such as compaction and cementation. The cycle includes three major categories of rocks - sedimentary, igneous, and metamorphic. Rocks may move between these categories over time due to changes in temperature, pressure, and chemical reactions.