Rocks

Rocks Naturally occurring Solid mixture Made of minerals, smaller rock fragments, organic matter, or glass

Rocks Grains Individual particles in rocks Texture Refers to grain size and how the grains are arranged

Rocks Igneous Rocks 1. Formation As magma or lava cools, mineral crystals form *Magma=molten rock inside earth *Lava=molten rock that erupts onto the surface

Rocks Igneous Rocks 2. Classification Igneous rocks are classified by texture

Rocks Extrusive Rocks Fine-grained Small crystals Formed from lava at the surface Cools quickly so crystals do not have time to increase in size

Rocks Intrusive Rocks Coarse-grained Large crystals Formed from magma below the surface Cools slowly so crystals have time to increase in size

Intrusive Extrusive Rocks INSIDE the Earth Rocks OUTSIDE the Earth Formed from magma Formed from lava Usually dark colored Usually light colored Usually dense Usually low density Mafic: magnesium and iron Felsic: feldspar Cools slowly Cools quickly Large grains Small or no grains (fine or glassy)

Rocks Igneous Rocks 3. Composition Minerals each rock contains Often visible by color

Rocks Metamorphic Rocks 1. Formation When parent rocks are heated, squeezed (pressure), or exposed to hot fluids (magma/lava) Rocks don’t melt but texture and composition can be changed

Rocks 2. Classification Foliated Metamorphic Rocks 2. Classification Foliated Distinct bands of light and dark minerals Results when uneven pressures cause flat minerals to line up Gives rock layered appearance

Rocks 2. Classification Nonfoliated Crystals become boxlike or square Metamorphic Rocks 2. Classification Nonfoliated Crystals become boxlike or square Not flattened

Rocks Metamorphic Rocks

Rocks Sedimentary Rocks Sediments Lithification Rock and mineral fragments that are loose and are suspended in water Lithification The process by which sediment turns into rock

Rocks Sedimentary Rocks 1. Formation Sediment formed by weathering Moved by water, ice and wind Deposited in low areas Layers build up Dissolved minerals cement grains together Sedimentation Deposition Compaction Cementation

Rocks 2. Classification Texture (size of grains) Sedimentary Rocks 2. Classification Texture Fine or coarse grained (size of grains) Rounded or angular grains (shape of grains)

Rocks 3. Composition Depends on minerals in the sediment Sedimentary Rocks 3. Composition Depends on minerals in the sediment

Sedimentary Rock Mini Lab Draw a 3 column chart. Column 1 can be small. List each rock number in column 1 on a chart. In column 2, describe each rock (2-3 bullet points). Describe texture (grain size and shape) as well as color. Gently scratch and #29 with the nail over black paper. What do you observe? Why does this happen? In column 3, explain why you think this rock is sedimentary. Use the characteristics of sedimentary rocks in your explanation.

Processes that change one rock type to another Rocks The Rock Cycle Processes that change one rock type to another

Rocks The Rock Cycle Cooling and Crystallization Uplift Weathering and Erosion Deposition Compaction and Cementation Temperature and Pressure Plate Tectonics

Rocks Cooling and Crystallization The Rock Cycle Cooling and Crystallization Extrusive: when lava erupts, cools, and crystallizes on the surface Intrusive: when magma cools and crystallizes inside earth

Rocks Uplift Moving large amounts of rock up to earth’s surface The Rock Cycle Uplift Moving large amounts of rock up to earth’s surface

Rocks Weathering and Erosion The Rock Cycle Weathering and Erosion Glaciers, wind, rain break down rock and carries it to low areas

Rocks Deposition Laying of down sediment in a new location The Rock Cycle Deposition Laying of down sediment in a new location Forms layers of sediment

Rocks Compaction and Cementation The Rock Cycle Compaction and Cementation Weight of layers compacts or pushes grains closer As they crystallize, layers cement

Rocks Temperature (Heat) and Pressure The Rock Cycle Temperature (Heat) and Pressure As temperature and pressure increase, rocks go through metamorphism

Rocks The Rock Cycle Plate Tectonics Processes that move tectonic plates also drive the rock cycle Main force = convection currents in the mantle