Presentation on theme: "Metamorphic Rocks Classified according to the arrangement of the grains that make up the rocks & the minerals in them A Rock Group in action…"— Presentation transcript:
Metamorphic Rocks Classified according to the arrangement of the grains that make up the rocks & the minerals in them A Rock Group in action…
Metamorphic rocks are nicknamed “Changing Rocks”. Why? They are made from other rocks…
How do Metamorphic rocks form? From heat & pressure deep inside Earth
Regional Metamorphism: Metamorphic rocks can form from Igneous, Sedimentary, or other Metamorphic rocks as they are pushed down toward the heat of the mantle.
Metamorphic Rocks: Contact Metamorphism Contacting hot magma can change the surrounding rocks…
Stage 1 Mineral Alignment Pressure Heat -Original parent rock with minerals in rock structure. (X,Y,Z). - Rock is subject to low grade pressure & temperatures & then the minerals are flattened. x Y x x x Y Y Y z z z z z x x z Formation of Metamorphic Rocks
Stage 2 Banding "Recrystallization" extreme heat & pressure allows individual crystals to… - Grow larger -Consolidate together -Separate according to density differences. z z z z z zz z zzz z z z zz z x x x x x x x x x x x x x x x Y Y Y YY Y Y Y YY z Y Y Y Y zz z z x xx x x x Y Y Y Y Y Y
2 Types of Metamorphic Rock Foliated Nonfoliated “Banded”“Nonbanded”
Foliated Metamorphic Rock Definition: Grains arranged in layers or bands that split into layers Examples: Slate Schist Gneiss
Original Rock New Metamorphic Rock Shale Slate Shale (sedimentary) changes to Slate when heated & squeezed by pressure.
Original Rock New Metamorphic Rock Granite Gneiss Granite (Igneous) changes to Gneiss when heated & squeezed by pressure.
Nonfoliated Metamorphic Rock Definition: Mineral grains arranged randomly, do not split into layers Examples: MarbleQuartzite
Original Rock New Metamorphic Rock Sandstone Quartzite When Sandstone (Sedimentary) is under extreme heat & pressure, Quartzite will form.