Types of Rocks and Rock Cycle PDF

# Rocks and the Rock Cycle ## Rock Classification - Rocks are classified by: - How they form - Texture - Grain size - Mineral composition ## Three Types of Rocks - Igneous - Sedimentary - Metamorphic ## Igneous Rocks - Igneous rock: forms when molten rock (magma) cools and hard...

# Rocks and the Rock Cycle ## Rock Classification - Rocks are classified by: - How they form - Texture - Grain size - Mineral composition ## Three Types of Rocks - Igneous - Sedimentary - Metamorphic ## Igneous Rocks - Igneous rock: forms when molten rock (magma) cools and hardens - Classified by: - Where they form - Crystal (grain) size - Hard and durable - Uses - building material ## Intrusive Igneous Rock - Intrusive igneous: cooling takes place slowly beneath Earth's surface (magma hardened beneath the surface of the Earth) - Forms coarse grained rocks with large crystals - Ex: granite, pegmatite ## Extrusive Igneous Rock - Extrusive igneous: cooling takes place rapidly on Earth's surface (lava that erupted onto Earth's surface) - Forms fine grained rocks with small or no crystals; glassy texture - Ex: basalt, rhyolite ## Sedimentary Rock - Sedimentary rock: forms from the compaction and/or cementation of sediments - This process is called lithification - Sediments are: - Rock pieces - Mineral grains - Shell fragments ## How do sediments form? - Sediments form through the processes of weathering and erosion of rocks exposed at Earth's surface ## Sedimentary Rock con't... - Sedimentary rock can also form from the chemical depositing of materials that were once dissolved in water - When water evaporates, minerals left behind form rock - Ex: shale, sandstone - Uses: tools and building materials ## Metamorphic Rock - Metamorphic rock: forms when any rock type is changed into a different kind of rock - Changes due to great heat and/or pressure - Uses: statues and buildings ## Metamorphic Cont. - Foliated - describes thin, flat layering - Ex: slate, gneiss - Nonfoliated - grains arranged randomly - Ex: marble ## How does rock change? - Rocks are heated, squeezed, folded, or chemically changed by contact with hot fluids - The deeper the rock is buried, the higher the pressure on the rock ## The Earth Recycles Rock - The rock cycle is an ongoing series of processes inside Earth and on the surface - Slowly changes rocks from one kind to another - Any type of rock can change into another type ## Rocks Foldable - Three tabs: - Type of rock - How they form - At least 2 examples ## Rock Cycle Poster - Draw a colorful diagram of the rock cycle; make sure to include: - 3 types of rocks - Erosion and weathering - Sediments - Compaction and cementation - Magma - Melting - Heat and pressure ## Test Your Skills - Bed Based on the processes shown in the diagram, which type of rock is formed at #1? - A. Sedimentary - B. Igneous - C. Metamorphic - D. Clastic - Because heat and pressure are needed to form #3, it must be what type of rock? - A. Sedimentary - B. Igneous - C. Metamorphic - D. Clastic