ROCKS

Rocks a naturally occurring solid mixture composed of minerals, smaller rock fragments, organic matter, or glass. Grains – individual particles in rock

Types of Rocks Igneous – most abundant on Earth Formation Molten rock (magma) erupts onto the earth (lava) and cools Texture/Composition Fine-grained (small crystals) Coarse-grained (large crystals)

Types of Rocks Sedimentary Formation Texture/Composition Lithification – process through which sediment (loose rock and mineral fragments) turn into rock Layers of sediment build up and the weight of top layers compact the sediments into rock Texture/Composition Fine or coarse grained Rounded (older) or angular (younger)

Types of Rocks Metamorphic Formation Texture/Composition Parent rocks are squeezed or heated forming new rocks Texture/Composition Foliation – uneven pressures cause flat minerals to line up, giving the rock a layered appearance

Uses of Rocks Hard and durable (granite, limestone) construction, building Soft with hard pieces (pumice) polishing/cleaning Foliated (slate) roofing shingles Soft (marble) carving/sculpturing

The Rock Cycle Series of processes that continually change one type of rock into another

Processes of the Rock Cycle Cooling and Crystallization Extrusive Rock – igneous rocks that form from lava that erupts, cools, and crystallizes on Earth’s surface Intrusive Rock – igneous rocks that form from magma that cools and crystallizes inside Earth

Processes of the Rock Cycle Uplift Process that moves large amounts of rock up to the Earth’s surface Associated with development of mountains Weathering and Erosion Breaking down and transporting of rock due to the environment (wind, glaciers, rain, organisms)

Processes of the Rock Cycle Deposition Process of laying down sediment in a new location Forms layers of sediment Compaction and Cementation Weight of overlying layers pushes grains of sediment closer together Crystallized minerals cement the grains together

Processes of the Rock Cycle Temperature and Pressure Rocks under high temperatures and pressures undergo metamorphism High enough temperatures cause the rocks to melt into magma to become igneous again

Rocks and Plate Tectonics Most changes to rocks occur at tectonic plate boundaries (volcanoes, mountains, earthquakes, etc.)