Rock Notes PDF

Rock Notes  A rock is a solid mineral material forming part of the Earth, either exposed on the surface or underlying in soils or oceans Types of rocks Igneous Sedimentary Metamorphic Crysta...

Rock Notes  A rock is a solid mineral material forming part of the Earth, either exposed on the surface or underlying in soils or oceans Types of rocks Igneous Sedimentary Metamorphic Crystallize from 3 Created by small Forms from High types of magma: pieces of rock that temperature and basaltic, andesitic were weathered and pressure and rhyolitic became cemented Can be foliated (has Creates 4 types of together layers and bands) or rock: basaltic, Clastic sedimentary non-foliated (has granitic, rocks are the most chunks) intermediate and common ultra basic Any rock can be changed The Rock Cycle into any other type of rock. This continuous changing and remaking of rocks is called the rock cycle. Igneous Rocks  Igneous Rock Igneous rocks form when lava or magma cools and minerals crystallize. Magma is classified as basaltic, andesitic, or rhyolitic, based on the amount of silica it contains. Silica affects melting temperature and impacts how quickly magma flows. Rocks melt at lower or higher temperatures because their component minerals have lower or higher melting points. EX) rocks that are rich in iron and magnesium melt at higher temperatures than rocks that contain higher levels of silicon. Crystal Size and Cooling rates Intrusive rocks are formed when magma cools and crystallizes below Earth’s surface. Extrusive Rocks form when magma that cools and crystallizes on Earth’s surface. When lava flows on Earth’s surface, it cools quickly and there is not enough time for large crystals to form. The resulting extrusive igneous rocks have crystals so small that they cannot be seen without magnification. Volcanic glass forms when lava cools so quickly that crystals do not form.  Types of Igneous Rock Basaltic Granitic Intermediate Ultrabasic dark-colored, have Rocks that have a rocks with only lower silica contents, light-colored, have composition of iron-rich minerals and contain mostly high silica contents, minerals that is such as olivine and plagioclase and and contain mostly somewhere between pyroxene and are pyroxene. quartz and feldspar. basaltic and granitic always dark. 1. 2. 3. 4. Sedimentary Rocks  Weathering, Erosion and Deposition Sediments are small pieces of rock that are moved and deposited by water, wind, glaciers, and gravity. Sediments are created through weathering (breakdown of materials) Erosion is the removal and transport of sediment. Deposition is when transported sediments are deposited on the ground or sink to the bottom of a body of water.  Lithification Lithification is the physical and chemical processes that transform sediments into sedimentary rocks. As more sediment is deposited in an area, the bottom layers are subjected to increasing pressure and temperature. Fossils are preserved in sedimentary rocks! Lithification begins with compaction. The massive weight of overlying sediments forces the sediment grains together, causing physical changes. Metamorphic Rocks  Metamorphic Rocks Metamorphic rocks form when high temperature and pressure combine and change a rock without melting it. Foliated metamorphic rocks are characterized by layers and bands of minerals caused by high pressure during metamorphism. Foliation develops when pressure is applied from opposite directions. Nonfoliated metamorphic rocks are composed mainly of minerals that form with blocky crystal shapes. EX) Quartzite and Marble.