topic 4 ( types of metamorphism )

• Impact (Shock) Metamorphism

  Metamorphism generated by meteorite impacts or explosive volcanic eruptions. Produces breccia, shocked quartz lamellae, Pseudotachylites, and UHP/UHT minerals; Impactites
• Dynamic Metamorphism

  High-strain rate metamorphism produced by non-uniform stress in fault and shear zones. 

  In low P-T (low depth), it produces Cataclasites. 

  At 5-10km, it produces Pseudotachylites

  At 10-15km, it produces Mylonites.
• Contact Metamorphism

  Local metamorphism around magmatic intrusion, typically producing an Aureole in the contact area between the intrusion and country rock. 

  Produces non-foliated metamorphic rocks such as Hornfels, Metaquartzite, and Skarns. 
• Ocean Floor Metamorphism

  Hydrothermal alteration (Metasomatism) at ocean spreading ridges resulting to alunitic, propylitic, Sericitic, silicification, carbonatization, serpentinization and Spilitization.
• Burial (Static) Metamorphism

  Increase in lithostatic stress by deep burial results in diagenetic processes (150oC – 350oC)
• Dynamothermal Metamorphism

  Regional metamorphism induced by increased temperature-pressure. It is the most aerially extensive metamorphism type. 
•  

  Type of metamorphism -Regional/ dynamothermal

  Condition- High pressure, high temperature, compression and shearing

  Occurrence - Occurs along convergent plate boundaries
•  

  Type of metamorphism - Contact/ thermal

  Condition- High temperature

  Occurrence- Occurs where plutons intrude
•  

  Type of metamorphism- Seafloor

  Condition- Metasomatism involved

  Occurrence- Occurs in mid-ocean ridges and igneous intrusions in continents
• Burial

  • condition is increasing pressure, temperature, and depth 
  • occurence is any
• Shock

  condition is Meteorite impact producing heat and shock wave

  occurence is any
• Dynamic

  • condition is No temperature or pressure involved, only shearing
  • occurence May be near the surface (fragmented) or at great depths (plastic)
• this is what it looks like

  
• this is what it looks like

  
• this is what it looks like