Rock Cycle Notes

Rock – earth material made up of minerals and organic matter (remains of once living organisms) Rock Cycle – a continuous process by which rocks are created, changed from one form to another, destroyed, and then formed again.

3 Types of Rocks Igneous Sedimentary Metamorphic

Igneous Rocks Formed from molten material (magma) Classification: Extrusive or Intrusive Extrusive igneous rock- comes out of a volcano, has small crystal grains because it cools QUICKLY Intrusive igneous rock- does not come out of the crust, cools SLOWLY underground so crystals have time to form and grow

Extrusive Igneous Rock (Obsidian) Intrusive Igneous Rock (Granite) EXAMPLES Extrusive Igneous Rock (Obsidian) Intrusive Igneous Rock (Granite)

Weathering, Erosion, & Deposition Weathering – break down of rocks Erosion – process in which rocks are transported from one location to another location by wind, water, or ice Deposition – geological process by which sediments, soil, and rocks are added to a landform or landmass

Sedimentary Rocks All types of rocks can be worn away by water and wind (weathering). Erosion is where the weathered bits are carried away. Deposition occurs when the weathered bits are dropped.

Sedimentary Rocks The weathered bits are carried away by water and are dropped out as the water flows. The biggest particles drop out first. This is how sediments build up and accumulate. Lithification – process by which sediments compact under pressure to form rock Sedimentary rocks form from the compaction and cementation of sediments and weathered rocks

SEDIMENTARY ROCKS Fossil formations are only found in sedimentary rock Conglomerate: has large pebbles cemented together Sandstone will have a gritty texture & can have layered stripes

Formed by heat and pressure Metamorphic Rocks Formed by heat and pressure Can occur at subduction zones (where one crustal plate slides underneath another) or in close proximity to a magma chamber There will be a change in the texture (appearance of rock) because the increased temperature and pressure causes minerals in the rock to become rearranged.

Magma chamber Types of subduction zones

Metamorphic rock Marble is formed when limestone is exposed to heat & pressure. Gneiss is a type of foliated (bands/stripes) metamorphic rock. It forms when granite is exposed to heat and pressure.