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WARM-UP #21 FEB. 9 The western part of California is located on a boundary between two tectonic plates. Would most of the metamorphic rock in that occur in small patches or wide regions? How do you know? Chapter 3 ROCKS ROCKS A rock is any solid mass of mineral or minerallike matter that occurs naturally as part of our planet. There are 3 major type: Igneous Sedimentary Metamorphic THE ROCK CYCLE Shows the relationship among the three rock types . Proposed by James Hutton in the late 1700s. Interactions among Earth’s water, air, land, and living things can cause rocks to change from one form to another The continuous processes that cause rock to change make up the rock cycle THE ROCK CYCLE Magma – molten material that forms deep beneath Earth’s surface Cools and hardens as the result of volcanic eruption Igneous rocks form Undergo weathering form Sedimentary rocks Sedimentary rocks in time morph into metamorphic rocks WEATHERING Process in which rocks are physically and chemically broken down What types of things do this? Water Air Living things Weathered materials are called sediments ROCK CYCLE The full rock cycle doesn’t always have to happen. Sedimentary rock can melt. Igneous rock can morph. Sedimentary and Metamorphic rocks can be weathered. DOES THAT ROCK HAVE A FUTURE? http://www.sascurriculumpathways.com Login, quick launch # is 71 Read the introduction pages Reseach and respond to the questions provided. Do this on a separate sheet of paper WARM-UP #19 FEB. 7 Texture and composition are two characteristics used to classify igneous rock Texture Coarse-grained Fine-grained Glassy Porphyritic Composition Granitic Basaltic Andesitic ROCKS Rocks are considered the building blocks of the Earth Rock is defined as a group of minerals bound together in some way There are three types TYPES Igneous Metamorphic Sedimentary IGNEOUS Igneous rocks form from magma Magma comes in different types Felsic Mafic There are 2 types of igneous rocks Intrusive Extrusive FELSIC MAGMA High in silicates Light in color Typically forms at the top of a magma chamber MAFIC MAGMA Low in silicates Higher in magnesium and iron Dark colored Typically forms at the bottom of the magma chamber INTRUSIVE Form underneath the Earth’s surface as magma cools and solidifies These rocks tend to have visible mineral crystals because of the slow cooling COMMON INTRUSIVE IGNEOUS ROCKS Granite Diorite Rhyolite EXTRUSIVE IGNEOUS ROCKS Forms outside Earth’s crust Cools quickly Very few mineral crystals are visible COMMON EXTRUSIVE ROCKS Obsidian Pumice Basalt DICHOTOMOUS KEY FOR IGNEOUS ROCKS Are your rock grains sandsized or smaller? Yes No Does your rock contain quartz? Yes Yes Does your rock look like black glass? Obsidian No Granite No Yes Is your rock mostly dark colored? Yes Basalt Gabbro No Diorite Will your rock float on water? No Does your rock contain quartz? Yes Rhyolite No Andesite WARM-UP #20 How do igneous, sedimentary, and metamorphic rocks differ? What powers Earth’s rock cycle? FEB. 8 SEDIMENTARY ROCKS All sedimentary rocks start as small pieces called sediment Sediment is then compacted and cemented into rocks FORMATION Weathering is usually the first step in the formation Chemical weathering takes place when minerals in rocks change into new substances Physical weathering takes place when minerals or rocks just break into smaller pieces FORMATION Sediment doesn’t usually stay in one place It is moved by water, wind, ice, gravity Erosion – weathering and removal When the agent of erosion loses power or energy, it drops the sediment FORMATION Compaction – process that squeezes sediments Cementation takes place when dissolved minerals are deposited in the tiny spaces among sediments CLASSIFICATION Two main categories Clastic Chemical CLASTIC Made by weathered bits of rocks and minerals Then grouped by size of the sediment Conglomerate – large rounded particles Breccia – angular pieces Sandstone – pieces the size of sand Shale – very fine-grained sediment Siltstone – another fine-grained category CHEMICAL Formed when dissolved minerals precipitate from water solutions Limestone METAMORPHIC ROCKS Formed when rocks and minerals undergo changes caused by heat, pressure and chemical fluids. METAMORPHISM Contact metamorphism Hot magma moves into rocks Brings minor changes Marble often forms from this Regional metamorphism Large-scale deformation and high-grade metamorphism May occur during mountain building AGENTS OF METAMORPHISM Heat – MOST IMPORTANT Provides energy to drive a reaction Comes from magma and change in temp. with depth Pressure – increases with depth Cause rock to flow Hydrothermal solutions CLASSIFICATION - TEXTURE Foliated More compact More dense Nonfoliated Doesn’t have a banded texture Contains only one mineral http://www.learner.org/interactives/rockcycle/ TICKET OUT THE DOOR 1. 2. Draw a quick sketch of the rock cycle. What types of things cause weathering and erosion
