Types of Metamorphic Rock
How metamophism effects different different types of rock
- Created by: Mellissa True
- Created on: 09-02-13 18:52
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- Types of Metamorphic Rock
- Metamorphism of Sandstones
- Sandstones vary in type but always have a high proportion of quartz
- Under the effects of heat and pressure grains tend to interlock and recrystallize to form metaquartzite.
- The colour of metaquartzite may may indicate how the original sandstone was cemented.
- Example: A reddish metaq. is likely to have come from a sandstone which has been cemented with iron minerals
- Sandstones vary in type but always have a high proportion of quartz
- Metamorphism of Limestones
- Limestone's form in a variety of ways but always contain calcite as their main mineral
- Both Regional and Thermal metamorphism can cause this calcite to recrystallise and form marble
- Pure Limestones form bright white marble with a sugary texture of interlocking calcite crystals.
- Muddier types of limestone tend to produce marbles with patches or streaks of coloured minerals from the recrystallisation of their clay minerals
- Limestone's form in a variety of ways but always contain calcite as their main mineral
- Metamorphism of Mudstones and Shales
- Mustones and shales are fine-grianed sediments composed of complex clay minerals. Different conditions can change these rocks in different ways.
- During Thermal Met. rocks close to the intrusion have complete recrystallisation so the resulting rock has an interlocking texture creating hornfels.
- Further away less change occurs and spotted rocks are formed. the "spots" are new minerals which have been able to form.
- Metamorphism of Sandstones
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