Metamorphic Rocks

Transforming Rocks Rocks change because of changes in temperature and pressure, or the presence of hot, watery fluids. Mineral grains of rocks are flattened and aligned when heat and pressure are applied. Rocks change because of changes in temperature and pressure, or the presence of hot, watery fluids. Mineral grains of rocks are flattened and aligned when heat and pressure are applied.

Heat & Pressure Temperature and Pressure increase as you travel deeper below the surface of the Earth. Heat and pressure sometimes cause rocks to melt = Igneous Rocks Temperature and Pressure increase as you travel deeper below the surface of the Earth. Heat and pressure sometimes cause rocks to melt = Igneous Rocks

In other areas, melting doesn’t occur = Mineral grain of rocks become flattened. During this process, minerals exchange atoms with surrounding minerals to form bigger mineral deposits. In other areas, melting doesn’t occur = Mineral grain of rocks become flattened. During this process, minerals exchange atoms with surrounding minerals to form bigger mineral deposits.

Example of Metamorphic Rock Formation Shale + Heat + Pressure = Slate Increasing Heat & Pressure: Slate + Heat + Pressure = Phyllite Phyllite + Heat + Pressure =Schist Schist + Heat + Pressure = Gneiss Shale + Heat + Pressure = Slate Increasing Heat & Pressure: Slate + Heat + Pressure = Phyllite Phyllite + Heat + Pressure =Schist Schist + Heat + Pressure = Gneiss

Hot Fluids Fluids can move through solid rock. These fluids are mostly water with dissolved elements. These fluids react chemically with the rock to change its composition without having to melt it. Fluids can move through solid rock. These fluids are mostly water with dissolved elements. These fluids react chemically with the rock to change its composition without having to melt it.

Classifying Metamorphic Rocks Classify metamorphic rocks according to their composition and texture. 2 Categories – Foliated and Nonfoliated. Classify metamorphic rocks according to their composition and texture. 2 Categories – Foliated and Nonfoliated.

Foliated Rock Mineral grains line up in parallel layers. Foliation = Bands Can easily separate along foliation layers (Roof and tiling). Ex: Slate and Gneiss. Mineral grains line up in parallel layers. Foliation = Bands Can easily separate along foliation layers (Roof and tiling). Ex: Slate and Gneiss.

Nonfoliated Rock Minerals grains grow and rearrange, but DO NOT form layers. Ex: Sandstone + Pressure = Quartzite Limestone + Heat + Pressure =Marble Minerals grains grow and rearrange, but DO NOT form layers. Ex: Sandstone + Pressure = Quartzite Limestone + Heat + Pressure =Marble