What is a Rock? It is a mixture of minerals and organic matter. Rocks are classified into 3 types by how they are formed. Igneous-cooling magma or lava Sedimentary- cemented and compacted fragments Metamorphic-heat and pressure
What are the processes that make or destroy rock?
Weathering Breaking down of rock by wind, water, ice, heat, animals.
Erosion Moving rocks and sediment from one location to another by wind, water, ice and gravity
Intrusive Igneous rocks Intrusive rocks cool slowly and crystals have time to grow larger.
Extrusive Rocks Extrusive rock crystals are small because rock was not given enough time to cool.
Magma types Basaltic(MAFIC)- thin, fast moving lava rich in iron and magnesium. Forms dark colored rocks. (Much like maple syrup) Granitic (FELSIC)- thick, slow moving magma rich in silicon and oxygen. Forms light colored rocks (More like molasses) Andesitic- magma with a mixed composition of basaltic and granitic.
Classifying Igneous rock 1. Look at crystal size. Intrusive or Extrusive? 2. Look at color of rock. Basaltic, Granitic or Andesitic?
4-3 Sedimentary Rocks 75% of all Rocks on Earth’s surface are sedimentary. Weathering and Erosion breaks particles into fragments. Particles are either cemented or compacted together to form rock. Sedimentary rocks contain fossils and give clues to what happened in Earth’s history. Most rocks found in our area are Sedimentary!!!
Types of Sedimentary Rocks Clastic- rock formed from broken fragments compacted and cemented.
Sediment Sizes Clastic Sedimentary rocks are classified by sediment size in the rock. Particles move into an ocean or lake and settle out by particle size and density. Largest particles near shoreline, finer and smaller farther out.