Lecture 10: META Rocks
- Old component of continental crust called "Craton".
=> Craton - AKA Shield, are continents that have been
stable for billions of years.
- META rocks contain mineral resources.
- Used for building materials such as statues.
- META rocks is the result from pre-existing rock.
- META rocks are altered/changed rocks.
- Heat and pressure creates META rocks.
- Are different from their rock parents (both chemically and
- Occurs deep inside the Earth.
- Don't need high or low temperature.
- META rocks are the "Middle Child" - Mid. Temperature and Mid.
=> SED rocks - shallow and low temperature.
=> Igneous rocks - need high pressure and high
- META rocks need to be put under pressure.
- Pressure controls primarily META rocks. - Two broad types of pressure exerted on rocks:
1. Confining Stress
2. Directed or Compression Stress
=> Found in Convergent Plate Boundary.
- Different from the Parent:
=> Higher density and minerals altered.
1. Non-Foliated - No orientation
=> Formed around igneous intrusion.
=> High Temperature and low pressure.
=> Ex: Quartzite, Marble, Hornfels.
=> No layered or banded appearance.
2. Foliated - Have layered or banded appearance from the
exposure to heat.
=> Layers are due to the pressure squeezing them flat.
=> Directed Minerals that don't melt will elongate and
=> Confining has high density and minerals are