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
Deposition When moving sediment comes to rest.
Uplift Upward movement of crust caused by plate movement.
Melting/Cooling of Rock Occurs near volcanically active areas or deep in Earth’s mantle.
Compaction/Cementation (Lithification) Hardening of moist sediment by pressure.
Heat and Pressure Partial melting of rock by heat of magma chambers or pressure from plate collisions.
Rock Texture Size of grains- larger or coarse to small or none. Shape of grains- rounded or jagged Pattern of grains- layered or non-layered Classified By:
Section 4-2 Igneous Rocks Where and how do igneous rocks form? From cooled lava or magma around volcanic regions. Igneous rocks are called Intrusive or Extrusive based on where they are formed.
Igneous video 1
Igneous video 2
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.
Sedimentary video #2
Key clastic Sedimentary rocks shale sandstoneconglomerate Rank the particle sizes of the rocks.
Chemical Sedimentary Rocks Formed from precipitated solution or evaporated solution. Usually have a smooth texture. Limestone Chert Rock salt
Organic Sedimentary rocks Compacted remains of once living things such as plants, shells, and microscopic organisms Coal Coquina Fossil-rich limestone
Section 4-4 Metamorphic Rocks Classes of Metamorphic Rock Foliated- mineral grains pressed into layers. Gives rock a “banded” appearance. Non-foliated- rock is “baked” and minerals re-arrange
Metamorphic video 1
Which is Foliated/Non-Foliated?
Formation Regional metamorphism= heat and pressure (extreme folding) Contact metamorphism= heat (surrounding rock cooked)
Metamorphic video #2
Mother Rocks Protolith- The rock that a metamorphic rock was formed from. The “Mother Rock” Sandstone- Quartzite Limestone- Marble Granite- Gneiss
TYPE OF COAL FORMED DEPENDS ON THE AMOUNT OF PRESSURE APPLIED TO MATERIAL!!!!