Formation and Characteristics

 “Meta” means change (Greek)  “Morph” means form (Greek)  A rock that has been changed from its original form (parent rock) by heat, pressure, and fluid activity into a new form (daughter rock).

 Contact – caused by proximity to igneous activity. Heat causes minerals to recrystallize but not melt.  Dynamic – associated with faults and earthquake zones  Regional – Caused by tremendous pressures associated with plate tectonics. Deep burial.

Progression of Metamorphism Start with a shale and then hit it with heat and pressure! Rock NameRock Type Grade of Metamorphism ShaleSedimentary----- SlateMetamorphicLow PhylliteMetamorphic Low/Intermediate SchistMetamorphic Intermediate/High GneissMetamorphicHigh Molten Rock Cools into Igneous Rock More Heat & Pressure

Shale (Sedimentary Rock) Slate (Metamorphic Rock) Heat & Pressure

Slate (Metamorphic Rock) Heat & Pressure Phyllite (Metamorphic Rock)

Phyllite (Metamorphic Rock) Schist (Metamorphic Rock) Heat & Pressure

… you end up with something that is really Gneiss!

 Foliated “Folios” means page, or leaf-like Rock has distinct layers  Often not smooth layers like sedimentary rock Formed under direct pressure (ex. Pushing down)  Non-foliated No distinct layers Often a massive crystalline structure Formed under uniform pressure (all directions)

Foliated Texture

Marble: - - metamorphosed limestone Quartzite: - - metamorphosed quartz sandstone Quartzite: - - metamorphosed quartz sandstone Non-foliated Rocks

 Rocks whose form is changed by temperature and pressure.  3 different types Contact Dynamic Regional  2 Textures Foliated Non-foliated  More temperature and pressure = more changes