Chapter 4 Rocks: Mineral Mixtures Standard S6E5.b Investigate the composition of rocks in terms of minerals EQ: How are rocks and minerals different? Section 1 pp.90, 95, 96 • Rock • Naturally occurring solid mixture of one or more minerals and organic (living) matter • What is the Rock Cycle? • Past uses for Rocks • Used to make… • The series of processes in which a rock forms, changes from one type to another, is destroyed, and forms again by geological processes. • Include hammers to make other tools • Make ancient and modern buildings & monuments • What is weathering? • Why is it important? • What is Erosion? • What is deposition? • The process in which water, wind, ice & heat break down rocks • It breaks down rock into fragments. This is the sediment from which SEDIMENTARY rocks are made. • Erosion is the process by which wind, water, ice, or gravity transports soil & sediment from 1 location to another. • Deposition is the process in which material is laid down. – Sediments may be pressed & cemented EQ: What is Uplift? • What is uplift? • What happens when uplift reaches the Earth’s surface? • It is movement within the Earth that causes rocks inside the Earth to be moved to the Earth’s surface • Weathering, erosion, and deposition begin EQ: How are rocks classified? • 3 Classes of Rocks 1. Igneous 2. Sedimentary 3. Metamorphic Rocks are classified by: • Composition • The chemical makeup of the rock –the minerals and other materials • Texture • The size, shape and positions of the rock grains • Provides clues as to how and where the rock is formed Warmup • Write a paragraph that: • Compares and contrasts minerals and rocks. EQ: Where do igneous rocks come from? Section 2: pg. 98-101 • Igneous Rocks • Igneous means “fire” • Begins as magma that contains many minerals • Cooled magma hardens and solidifies (becomes a solid) Igneous Rock Composition • Composition of Igneous Rocks • Determined by minerals • Light colored ones – less dense– made of aluminum, silicon-Felsic Rocks • Dark colored ones – more dense, made of iron, calcium, & magnesiumMafic Rocks Igneous Rock Texture • Texture of Igneous Rocks • Size of the grains • Fast cooling lava on the surface of the volcano -fine grains or no grains Ex: pumice • Slow cooling magma inside the Earth -large grains Ex: granite Igneous Rock Formation • Igneous Rock Formation • Intrusive igneous rock – forms inside Earth – cools slowly – Many are named for their size & shape – Large (coarse) grains • Ex: granite • Igneous Rock Formation • Extrusive Igneous Rock – – forms on Earth’s surface – Common around volcanoes – cools fast – fine grains or no grains Ex: pumice • Igneous Rock Formation • In other words, the faster the magma or lava cools the smaller the grains of the rock • The slower the magma or lava cools the larger the grains of the rock Summary • Compare and contrast Stone Mountain’s granite and pumice from a volcano. Draw a Picture of the Formation of Igneous Rocks • Label intrusive, extrusive, magma, lava. • Show the grain size of the developing rocks. • Indicate how fast the rocks cool. • Name rock samples for each class of igneous rocks. EQ: What are sedimentary rocks made of? Section 3 pg. 102 – 105 • Sediments • Fragments of weathered rock & minerals • Strata • Layers of sedimentary rock on Earth’s surface that forms when the sediment is deposited & cemented together by dissolved clacite & quartz • Stratification • Process in which sedimentary rocks are arranged in layers • What do they record? • Motion of wind & water waves on oceans, rivers, and sand dunes EQ: What are the 3 classes of sedimentary rock? • Clastic • Made of rock fragments cemented together by dissolved calcite & quartz • May be any grain size • Examples: conglomerate, shale, sandstone • Chemical • From solutions of dissolved minerals in water • The dissolved minerals crystallize • Ex: halite—salt— NaCl Result of supersaturated salt water • Organic • Made from the remains of dead organisms • Ex: Chalk is made of tiny sea creatures • Ex: Coal forms underground when decomposed plant material is changed into coal by heat & pressure Fossil fuels are nonrenewable resources Summary • Describe the formation of the 3 classes of sedimentary rock. • Draw a picture of how each sedimentary rock forms • Show the rock “before” it became a sedimentary rock and the “after” or the resulting sedimentary rock. • Label each class of sedimentary rock. • Compare and Contrast Igneous and Sedimentary Rocks EQ: What is metamorphism? Section 4 pg. 106 – 111 • Metamorphism • Change shape • Metamorphic Rock • The structure, texture or composition of the rock changes because of extreme heat and/or pressure • A chemical change occurs • Deformation • Change in the shape of a rock caused by a force, like squeezing or stretching EQ: What are the 2 classes of metamorphic rock? • Foliated • Mineral grains are arranged in bands • Ex: mica, slate • Non-foliated • Random arrangement of grains • Commonly made of 1 or a few minerals • Ex: marble Summary • If I needed to make a tool from a rock, should I choose a foliated or a non-foliated metamorphic rock? Explain your answer.