What are Metamorphic Rocks? How are they Classified?

Metamorphic Rocks Previously existing Rocks changed due to Heat and Pressure. Metamorphism – Change form

Metamorphism - Change form FROG BUTTERFLY

ROCKS IGNEOUS METAMORPHIC

SEDIMENTARY Metamorphic

Regional Metamorphism Enormous amounts of Heat and Pressure usually associated with Mountain Building and colliding crustal plates. Regional metamorphism and plate movements Heat source comes from the friction with the overlying rock layers and pressure from those layers

Effects of Regional Metamorphism Density increases because the grains are pushed closer to each other. The pressure produces foliation and banding **Foliation – alignment of mineral grains **Banding light and dark layers of recrystallized minerals Distorted Layers

Effects of Regional Metamorphism Density Increases b/c the grains are pushed closer together Banding Formation Regional Metamorphism and depths of formation

Distorted Banding

CONTACT METAMORPHISM Metamorphism due to contact with extreme temperatures due to contact with Magma, Lava, or Heated water near hydrothermal vents. Contact Metamorphism watch contact metamorphism occur

Transition zones Metamorphic Rocks will form where Igneous Rock meets Sedimentary Rocks, because the Igneous Rocks provided the heat to change the sedimentary rock into a metamorphic rock.

Most Metamorphic Rocks are Regional Since regional metamorphism affects wide areas of rocks being squeezed and together most metamorphic rocks are regional. Contact Metamorphic rocks will only form in the boundaries btn Igneous intrusions and sedimentary layers.